# Description

Touch Fraction:

Interactive fraction.

About fractions, and the construction of the rational numbers: ℚ set.

To play with proper and improper fractions, positive and negative also.

All fractions in order from least to greatest. You can increase or decrease the fractions included in the app, increasing or decreasing the density of lines in the lower graph framework. The accuracy of the application depends on the capabilities of the device.

The application lets you play with fractions: Provides two representations: a circle and a straight line whose has the slope of chosen fraction

Spin the fraction: You can choose different fractions in order from low to high within the possibilities included in the grid at the bottom formed by pairs of integers.

Select equivalent fractions with the rational representation diagram (the lower grid).

Change range of fractions affordable with a "pinch zoom" on the lower grid.

In the vertical strip of the grid graph goes from 0 to 1 you can see the number of units containing the selected improper fraction: Each unit is a black square.

The program is useful to understand: fractions, coordinate geometry, rational numbers, cartesian plane, slope, and the equivalent classes of pairs of integers.

Nummolt construction toys:

http://www.nummolt.com

MathTools reference:

http://mathforum.org/mathtools/tool/200416/

Math 1 Fractions

Math 2 Fractions

Math 3 Fractions

Math 4 Fractions

Math 5 Fractions

Math 6 Fractions, Rect coordinate geometry

Math 7 Rational numbers, Fractions, Linear relationships, Ratio and proportion, Rect coordinate geometry

Geometry Points and lines, Cartesian plane, Slope

Algebra Whole, Rational

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# Reviews

Helpfulness

Newest

Rating

Helpfulness

All Versions

All Versions

Latest Version

3.1

10 total

5 3

4 1

3 2

2 2

1 2

User reviews

nummolt November 12, 2013

Spin the fraction: You can choose different fractions in order from low to high within the possibilities included in the grid below formed by pairs of integers.
Select equivalent fractions with the rational representation diagram (the lower matrix of lines).
Change range of fractions affordable with a "pinch zoom" on the lower grid.
Thanks! # What's New

v1.3 optimized for 10 in. tablets

v1.2 minor improvements.

v1.1 interaction improved.

v1.0 first version

# Additional information

Updated

April 14, 2014

Size

264k

Installs

1,000 - 5,000

Current Version

1.3

Requires Android

2.2 and up

Content Rating

Everyone

Permissions

Report

Flag as inappropriate Offered By

nummolt

Developer

Visit Website Email nummolt@gmail.com Privacy Policy

C/ Sant Antoni Maria Claret, 324 porta 46
Barcelona 08041 SPAIN

# Similar

## Fractions Math

GK Apps

1

This free math app is a fractions calculator with various functions:

- add, subtract, multiply and divide fractions.

- convert fractions in decimals,

- simplify fractions

- compare fractions

- find the lowest common denominator

- fraction trainer, to learn fraction calculations

Best mathematical tool for school and college! If you are a student, it will helps you to learn arithmetics and calculations with fraction numbers.

Note: A common fraction consists of an integer numerator, displayed above a line (or before a slash in this app), and a non-zero integer denominator, displayed below (or after the slash) that line. Numerators and denominators are also used in fractions that are not common, including compound fractions, complex fractions, and mixed numerals.

## Simply Fractions 2 (Lite)

Simply Fractions 2 is designed for second grade to fourth grade elementary students to further their understanding of fractions, it is the next step from the Simply Fractions app.

Kids will learn about mixed fractions, equivalent fractions, fractions on a number line, a fraction of a collection whose size is greater than the denominator, compare fractions with different numerators and denominators, but can be compared to either 0, 1/2 or 1. We use a scaffolding approach, where the concept is introduced visually first, later there will be games without visual aid to strengthen the concept learned.

The full version has eight different mini activities. The lite version has 2 mini activities, no ads are served in either versions.

Here is a summary of the activities:

1. Shade Fractions 2: Like in Simply Fractions 1, you are asked to shade the squares, but the number of squares is larger then the denominator. They are arranged so you can easily see the grouping.

2. Mixed Fractions: You are presented with circles and a fraction of a circle, you will have to put in the correct whole number, numerator, denominator and the equivalent simple fraction's numerator and denominator. Since you are asked to put in the number rather than choosing from multiple choices, guessing is minimized.

3. Number Line: You have to put in the numerator based on the position on the number line, hints are provided so you will see the fraction on the number line is the same as a fraction of a whole. You will compare the fraction to a half, so you will be prepared to do the harder part of the compare exercises.

4. Fraction of a Set 2: Like in Simply Fractions, you are asked to color a fraction of objects, but the number of objects is larger than the denominator. You can rearrange the objects into separate groups so you can color the right amount of them.

5. Equivalent Fractions: You are asked to put in the numerator to make an equivalent fraction based on the visual model presented.

Kids will learn about mixed fractions, equivalent fractions, fractions on a number line, a fraction of a collection whose size is greater than the denominator, compare fractions with different numerators and denominators, but can be compared to either 0, 1/2 or 1. We use a scaffolding approach, where the concept is introduced visually first, later there will be games without visual aid to strengthen the concept learned.

The full version has eight different mini activities. The lite version has 2 mini activities, no ads are served in either versions.

Here is a summary of the activities:

1. Shade Fractions 2: Like in Simply Fractions 1, you are asked to shade the squares, but the number of squares is larger then the denominator. They are arranged so you can easily see the grouping.

2. Mixed Fractions: You are presented with circles and a fraction of a circle, you will have to put in the correct whole number, numerator, denominator and the equivalent simple fraction's numerator and denominator. Since you are asked to put in the number rather than choosing from multiple choices, guessing is minimized.

3. Number Line: You have to put in the numerator based on the position on the number line, hints are provided so you will see the fraction on the number line is the same as a fraction of a whole. You will compare the fraction to a half, so you will be prepared to do the harder part of the compare exercises.

4. Fraction of a Set 2: Like in Simply Fractions, you are asked to color a fraction of objects, but the number of objects is larger than the denominator. You can rearrange the objects into separate groups so you can color the right amount of them.

5. Equivalent Fractions: You are asked to put in the numerator to make an equivalent fraction based on the visual model presented.

6. Compare: There are two modes, easy and hard. But in both modes you will need to rearrange the fractions into the right order. The easy mode, you will be asked to compare fractions with either the same numerators or the same denominators, these concepts were introduced in Simply Fractions, but here no visual aid is provided. The hard mode, the numerators and denominators are different, but they can be compared to a half, this is a crucial comparison strategy at this age.

7. Odd one out: You are provided with 4 fractions, you are to eliminate the one that is different than the other three equivalent fractions.

8. Equivalent memory: A classic memory game where you find pairs of equivalent fractions, this will strengthen the equivalent fractions skills.

No kids should feel dumb because they don't understand math, many times we fail them because we let them learn the next concept before they grasped the first concept. We hope to instill confidence and joy in children as they travel the long educational journey.

This app is optimized for both phones and tablets.

Keywords: common core, fractions, second grade math, third grade math and fourth grade math

## Simply Fractions (Lite), Math

Find Fractions too abstract? Is Math hard and boring? Not when you can see and play your way through the concept. Simply Fractions will help elementary school aged children understand and grasp the concept of fractions through hundreds of fun exercises.

Kids will be introduced to the concept of fractions through shapes like squares, circles, triangles, rectangles and polygons. Kids will also learn fractions of a set and fraction of a whole through the use of a beaker, and compare simple fractions. Also they will memorize the name of fractions with a fun memory game.

Fraction is a foundational concept in math, once it is seen and intereacted with, kids will find it more intuitive, not something boring and intimidating.

This app is designed for kids from Kindergarten through 3rd grade. The Full version has 7 different mini activities. The lite version has 3 mini activities, no ads are served.

This app is optimized for both phones and tablets.

keywords: kids fractions, math skills, learn fractions

Kids will be introduced to the concept of fractions through shapes like squares, circles, triangles, rectangles and polygons. Kids will also learn fractions of a set and fraction of a whole through the use of a beaker, and compare simple fractions. Also they will memorize the name of fractions with a fun memory game.

Fraction is a foundational concept in math, once it is seen and intereacted with, kids will find it more intuitive, not something boring and intimidating.

This app is designed for kids from Kindergarten through 3rd grade. The Full version has 7 different mini activities. The lite version has 3 mini activities, no ads are served.

This app is optimized for both phones and tablets.

keywords: kids fractions, math skills, learn fractions

## Fraction Calculator by Mathlab

Fraction calculator with step-by-step operations and algebra. Shows results as you type. Use space to enter mixed fractions. Graphical display of expressions with history.

Help site with instructions and examples: http://frac.mathlab.us

If you have a question, send email to calc@mathlab.us

FRACTION CALCULATOR

* Step-by-step operations (option to turn off)

* Arithmetic operations (+,-,*,/,÷), hold / to enter ÷

* Powers of fractions

* Fractions simplification

* Fractions with complex numbers

* Decimal to fraction conversion and back

* Symbolical fractions and operations

* Integer roots simplification

* Pinch to zoom

ALGEBRA

* Linear equations x+1=2 -> x=1

* Quadratic equations x^2-1=0 -> x=-1,1

* Approximate roots of higher polynomials

* Systems of linear equations, write one equation per line, x1+x2=1, x1-x2=2

* Polynomial long division

* Polynomial expansion, factoring

* Solving inequalities with one variable, double tap ( and ) to enter less and greater signs

* Linear and polynomial inequalities, x^3-4>4

* Inequalities with absolute values, abs(2x+3)<=5

* Compound inequalities, 1* Rational inequalities, (x+3)/(x-1)<=0

## Simply Fractions 3 (Lite)

Simply Fractions 3 is designed for fourth and fifth grade elementary students to further their understanding of fractions, it is the next step from the Simply Fractions 2 app.

Kids will learn visually how to add, subtract simple or mixed fractions with like denominators, multiply fractions by a whole number, solve word problems, learn about 10th and 100th based decimals, convert fractions to these decimals, compare the decimals, and add 10th based fractions to 100th based fractions.

Kids will learn visually how to add, subtract simple or mixed fractions with like denominators, multiply fractions by a whole number, solve word problems, learn about 10th and 100th based decimals, convert fractions to these decimals, compare the decimals, and add 10th based fractions to 100th based fractions.

The Full version has eight different mini activities. The lite version has 2 mini activities, no ads are served in either versions.

Here is a summary of the games:

1. Add fractions with like denominators, drag all the fractional pieces from the second operand to the first to see the visual model, then key in the right value. There are 4 levels of difficulty, from simple fractions to mixed fractions. This activity with all levels is available in the lite version also.

2. Subtract fractions with like denominators, take the fractional parts from the first operand to see the visual representation, then key in the right values. There are two levels of difficulty.

3. Multiply fraction by a whole number, drag all the fractional parts to the result panel to see the visual help, then key in the right values. There are two levels of difficulty.

4. Word problems, solve real world problems involving fractions using the add, subtract and multiply skills learned.

5. 10th and 100th. In this game, you are asked to shade 10th or 100th based fractions, you can also set the format to decimals, English word notation, or convert 10th to 100th or vice versa. This activity with all options is available in the lite version also.

6. Learn number line for 10th or 100th fractions and decimals.

7. Decimal sequence, compare decimals to hundredths and put them in order.

8. Add 10th and 100th, express a fraction with denominator 10 as an equivalent fraction with denominator 100, and use this technique to add two fractions with respective denominators 10 and 100.

This app is optimized for both phones and tablets.

keywords: common core, fractions, third grade math, fourth grade math, fifth grade fractions,

## Fraction Simplifier!

This app will simplify fractions (mixed, proper, & improper) and tell you if the fraction that you entered is already in simplest form. Also, just added, you can enter any decimal and it will automatically convert it into simplest fraction form. It will also convert rational, repeating decimals for you!

## Grade 1 Math: Fraction

Grade 1 Math - Fraction is an interactive app for kids in grade 1. This app provides an exciting way for kids to learn Fraction:

- Halves, Thirds and Fourths

- Equal Parts

- Simple Fractions

- Compare Fractions

- Fraction Word Problems

- Equivalent fractions

Downloading Grade 1 Math - Fraction will certainly be a correct choice for parents who are in search the educational apps for kids in grade 1. Learning is fun with this particular member of free apps that aim for kid’s learning everywhere.

Have questions, suggestions or concerns? Please email us and we’ll be happy to help!

- Halves, Thirds and Fourths

- Equal Parts

- Simple Fractions

- Compare Fractions

- Fraction Word Problems

- Equivalent fractions

Downloading Grade 1 Math - Fraction will certainly be a correct choice for parents who are in search the educational apps for kids in grade 1. Learning is fun with this particular member of free apps that aim for kid’s learning everywhere.

Have questions, suggestions or concerns? Please email us and we’ll be happy to help!

## Fraction Converter

GK Apps

1

This free mathematical calculator is able to convert:

- Fractions to Decimal numbers

- Decimal numbers to Fractions

- Fractions to Percent

- Percent to Fractions

Best math tool for school and college! If you are a student, it will help you to learn arithmetic and division!

Note: A common fraction consists of an integer numerator, displayed above a line (or before a slash in this app), and a non-zero integer denominator, displayed below (or after the slash) that line.

## Slice Fractions

Ululab

1

Get your child excited about his or her next math discovery through this award-winning, problem solving game. We’ve teamed up with university education experts to craft an incredibly fun way to learn fractions.

*** Editor’s Choice for Excellence in Design -- Children’s Technology Review ***

*** Winner of a Parents’ Choice Gold Award 2014 ***

*** Gold Medal Winner 2014 -- International Serious Play Awards ***

*** Best Family Friendly Game 2014 -- Indie Prize Showcase Awards ***

“Teaching without making it feel like a lesson.” -- maclife.com

“Slice Fractions is wholly playful learning. At its best.” -- Parents' Choice

“There's a lot more to this app than fractions.” (98%) -- Children’s Technology Review

Slice through ice and lava to clear the mammoth’s path, unraveling the mystery of fractions!

You will enjoy:

• Learning fraction concepts without words

• Experiencing an activity reviewed by researchers at a Canadian university (UQAM)

• Collecting funky hats

• Solving over 90 innovative physics puzzles

• Playing in a safe, digital environment. No ads or in-app purchases.

The game covers the following fraction concepts:

• Part-whole partitioning

• Numerator / Denominator notation

• Equivalent fractions

• Fraction ordering

• Subtracting fractions from 1

Teachers

Slice Fractions is based on the following Common Core concepts: (2.G.A.2) (2.G.A.3) (3.NF.A.1) (3.NF.A.3) (4.NF.A.1) (4.NF.A.2) (4.NF.B.3)

Google Play for Education Kickstart Guide: http://g.co/play/edukickstart

About Ululab

Ululab is a studio that produces fun and pedagogically sound video games. We strive to ensure that these games are intuitive and will lead to profound conceptual learning. We believe we can push the limits of game-based learning.

Follow us

Website: www.ululab.com

Twitter: twitter.com/Ululab

Facebook: www.facebook.com/Ululab

Newsletter: www.ululab.com/newsletter

Your feedback is much appreciated, so please feel free to provide suggestions for future updates. If something isn't working as you would expect, please contact us: www.ululab.com/contact

*** Editor’s Choice for Excellence in Design -- Children’s Technology Review ***

*** Winner of a Parents’ Choice Gold Award 2014 ***

*** Gold Medal Winner 2014 -- International Serious Play Awards ***

*** Best Family Friendly Game 2014 -- Indie Prize Showcase Awards ***

“Teaching without making it feel like a lesson.” -- maclife.com

“Slice Fractions is wholly playful learning. At its best.” -- Parents' Choice

“There's a lot more to this app than fractions.” (98%) -- Children’s Technology Review

Slice through ice and lava to clear the mammoth’s path, unraveling the mystery of fractions!

You will enjoy:

• Learning fraction concepts without words

• Experiencing an activity reviewed by researchers at a Canadian university (UQAM)

• Collecting funky hats

• Solving over 90 innovative physics puzzles

• Playing in a safe, digital environment. No ads or in-app purchases.

The game covers the following fraction concepts:

• Part-whole partitioning

• Numerator / Denominator notation

• Equivalent fractions

• Fraction ordering

• Subtracting fractions from 1

Teachers

Slice Fractions is based on the following Common Core concepts: (2.G.A.2) (2.G.A.3) (3.NF.A.1) (3.NF.A.3) (4.NF.A.1) (4.NF.A.2) (4.NF.B.3)

Google Play for Education Kickstart Guide: http://g.co/play/edukickstart

About Ululab

Ululab is a studio that produces fun and pedagogically sound video games. We strive to ensure that these games are intuitive and will lead to profound conceptual learning. We believe we can push the limits of game-based learning.

Follow us

Website: www.ululab.com

Twitter: twitter.com/Ululab

Facebook: www.facebook.com/Ululab

Newsletter: www.ululab.com/newsletter

Your feedback is much appreciated, so please feel free to provide suggestions for future updates. If something isn't working as you would expect, please contact us: www.ululab.com/contact

## Simplify Fractions Calculator

GK Apps

1

This free math calculator is able to simplify fractions. Just enter the fraction, click the button and the app will simplify.

Best mathematical tool for school and college! If you are a student, it will helps you to learn arithmetics and calculations with fraction numbers.

Note: A common fraction can be reduced to lowest terms by dividing both the numerator and denominator by their greatest common divisor.

## Fraction to Decimal

GK Apps

1

This free math calculator is able to convert fractions into decimal numbers. You can convert common fractions (like 1/2) and mixed fractions (like 2 4/5).

The best mathematical tool for school and college! If you are a student, it will help you to learn arithmetic and division!

Note: A common fraction consists of an integer numerator, displayed above a line (or before a slash in this app), and a non-zero integer denominator, displayed below (or after the slash) that line. Numerators and denominators are also used in fractions that are not common, including compound fractions, complex fractions, and mixed numerals.

## Fraction

This is a cool Math learning and practice app for children for learning fraction. The app teaches fraction in 4 parts:

• What is Fraction: Understand how to find fraction through simple shapes.

• Color the Fraction: Practice fraction through coloring certain part of a shape.

• Park the Cars: Practice fraction and strengthen your base by finding out certain fraction of group of cars and park them correctly.

• Fraction of a group: Understand how to find fraction of a number or group by finding fraction part of a group.

The app monitors child's progress and points out mistakes. If the child is not able to solve a given problem, it will explain that problem in a step by step manner in an animated way.

• What is Fraction: Understand how to find fraction through simple shapes.

• Color the Fraction: Practice fraction through coloring certain part of a shape.

• Park the Cars: Practice fraction and strengthen your base by finding out certain fraction of group of cars and park them correctly.

• Fraction of a group: Understand how to find fraction of a number or group by finding fraction part of a group.

The app monitors child's progress and points out mistakes. If the child is not able to solve a given problem, it will explain that problem in a step by step manner in an animated way.

## Simply Fractions, math games

Find Fractions too abstract? Is Math hard and boring? Not when you can see and play your way through the concept. Simply Fractions will help elementary school aged children understand and grasp the concept of fractions through hundreds of fun exercises.

Kids will be introduced to the concept of fractions through shapes like squares, circles, triangles, rectangles and polygons. Kids will also learn fractions of a set and fraction of a whole through the use of a beaker, and compare simple fractions. Also they will memorize the name of fractions with a fun memory game.

Fraction is a foundational concept in math, once it is seen and intereacted with, kids will find it more intuitive, not something boring and intimidating.

This app is designed for kids from Kindergarten through 3rd grade. The Full version has 7 different mini activities. The lite version has 3 mini activities, no ads are served.

This app is optimized for both phones and tablets.

keywords: kids fractions, math skills, learn fractions

Kids will be introduced to the concept of fractions through shapes like squares, circles, triangles, rectangles and polygons. Kids will also learn fractions of a set and fraction of a whole through the use of a beaker, and compare simple fractions. Also they will memorize the name of fractions with a fun memory game.

Fraction is a foundational concept in math, once it is seen and intereacted with, kids will find it more intuitive, not something boring and intimidating.

This app is designed for kids from Kindergarten through 3rd grade. The Full version has 7 different mini activities. The lite version has 3 mini activities, no ads are served.

This app is optimized for both phones and tablets.

keywords: kids fractions, math skills, learn fractions

# More from developer

## Time Calculator

nummolt

1

Time Elapsed / Time Countdown Time Calculator

With the Time Calculator you can calculate the subtraction between 2 dates:

You can fix a date in the past and subtract it from the present time: You get the elapsed time.

You can fix a date in the future and subtract the present time: You get the countdown to the fixed date.

(Light gray dates are in the past; Light green dates are in the future)

Don't work for dates earlier than 1582.

(Because the Gregorian Calendar)

Android version of:

http://www.mathcats.com/explore/elapsedtime.html

and:

http://www.nummolt.com/obbl/time/calculator.html

A work in collaboration www.mathcats.com and www.nummolt.com

(Wendy Petti and Maurici Carbó)

Practical applications proposed by users:

-. Useful to calculate demurrage. (http://en.wikipedia.org/wiki/Demurrage)

-. To calculate amount of pills of a medical treatment.

-. Calculate the number of days, or hours, or minutes, or seconds, remaining until retirement.

-. How old am I?

-. How old are you?

-. How many months, or weeks, or days, or hours, or minutes, or seconds are there in 1000 years?

-. Estimate the number of heartbeats throughout life at this time.

- multiplying lived minutes by a number between 60 and 100 for human beings.

- minutes, multiplied by 500 in the case of mice.

- minutes, multiplied by 28 in the case of elephants.

- minutes, multiplied by 6 in the case of the giant Galapagos tortoise.

-. Estimate the number of breaths made throughout life at this time: (for human beings)

- birth to 6 weeks: 30–60 breaths per minute

- 6 months: 25–40 breaths per minute

- 3 years: 20–30 breaths per minute

- 6 years: 18–25 breaths per minute

- 10 years: 15–20 breaths per minute

- adults: 12–20 breaths per minute

## Reading fractions

nummolt

1

Read fractions - Reading fractions

Basic tool for to experiment with fractions:

The app lets you view the fractions represented in the form of overlapping circles and bars.

The two graphs are interactive. They can be changed by dragging on the screen.

Graphically, fractions are always shown in simplified form.

There are two spinners to select fractions: one for the numerator and one for the denominator.

At the right there are two lock buttons:

The top button locks the numerator when the graph is modified.

The lower button locks the denominator when the graph is modified.

When both buttons are unlocked, the fractions are formed from the denominator 360 (the maximum allowed in the program) when the graph is modified.

When the two buttons are locked, the program always remains under the same fraction, but expresses its equivalent fractions in the spinners.

When the fraction expressed in the spinners is not in its simplified form, can be simplified by clicking on the simplified expression on his left.

Basic tool for to experiment with fractions:

The app lets you view the fractions represented in the form of overlapping circles and bars.

The two graphs are interactive. They can be changed by dragging on the screen.

Graphically, fractions are always shown in simplified form.

There are two spinners to select fractions: one for the numerator and one for the denominator.

At the right there are two lock buttons:

The top button locks the numerator when the graph is modified.

The lower button locks the denominator when the graph is modified.

When both buttons are unlocked, the fractions are formed from the denominator 360 (the maximum allowed in the program) when the graph is modified.

When the two buttons are locked, the program always remains under the same fraction, but expresses its equivalent fractions in the spinners.

When the fraction expressed in the spinners is not in its simplified form, can be simplified by clicking on the simplified expression on his left.

Additionally fractions are shown in written words, mixed fractions (if needed) as a percentage and as a decimal number with dot.

Fractions in words: Available in English, Catalan, Castilian (spanish), and French.

From www.nummolt.com

## Circadian clock

nummolt

1

The mechanism :

The green outer ring with 5 primary partitions and and 300 smaller partitions gives 59/300 turns per minute counterclockwise: 11.8 turns per hour.

The planetary gear of the seconds, in green color, is driven by the outer ring and gives 59 rph counterclockwise. And in turn, the axis makes a complete turn clockwise, rolling on the inside of the crown of the minutes, by hour.

The hand of the minutes, in blue color, turning on the central axis and linked to the axis of the planetary gear of the seconds, makes a complete turn every hour.

The wheel that rotates clockwise integrally with its base and with the hand of the minutes, make to spin counterclockwise two blue planetary wheels. These two planetary wheels spins counterclockwise a third planetary gear.

The third planetary wheel rotates one turn per hour clockwise and transmits the rotation to the fourth planetary wheel. The fourth planetary wheel spins counterclockwise and progresses clockwise.

The fourth blue planetary wheel gives 2 turns on itself and its axis gives the entire turn around the sphere of the clock every 12 hours.

On the four planetary wheels is mounted the hour hand: a big red triangle, giving rigidity to the structure and indicating the hours and rotating clockwise.

The big red triangle, linked to a freewheel on the central axis, drives the rotation of the three static planetary yellow wheels of the day. Turning counterclockwise about its fixed axis, rotates counterclockwise the yellow big crown that distinguishes the day light hours, of the darkness of the night and makes a complete turn every 24 hours.

The big red triangle, also linked to another freewheel on the central axis, drives the rotation of three static planetary wheels magenta of the week, much bigger than those for the day. Turning counterclockwise about its fixed axis, and spinning counterclockwise the crown magenta indicating the day of the week, and makes a complete turn every week.

Interaction:

Buttons:

The buttons are used to toggle the different layers of the watch:

-. Blue hand of minutes, and the green planetary gear of the seconds

-. Green crown of the seconds.

-. Static blue sphere of the hours and the minutes.

-. Planetary gear set and red triangle of the hours.

-. Planetary gear set in yellow color, and yellow crown of the day and the night

-. Planetary gear set in magenta color, and yellow crown of weekday.

-. Clock base body.

Dragging:

-. Dragging a finger, you can move the clock from its initial position.

-. Joining or separating and sliding two fingers on the screen, reduce or increase the size of the watch.

-. Dragging and rotating about the central axis with the finger on the red triangle of the hours, you can change the time. After removing the finger, the 'circadian clock', will slowly readjusting to redial the actual system time.

Circadian Clock:

www.nummolt.com

Technical drawings for the Circadian Clock:

http://www.nummolt.com/CircadianClock/

© 2014 Maurici Carbó, architect.

http://nummolt.blogspot.com/2014/03/posted-new-circadian-clock-at-google.html

Notes from developer:

The term 'circadian' comes from the Latin 'circa', meaning "around" (or "approximately"), and 'diem' or 'dies', meaning "day".

This app is only a clock, with many layers, showing many overlapped mechanisms, with zoom. The triangle of the hours is manually adjustable, and has an algorithm to reset the clock to the system time after any adjustment.

Nothing concerning the biological circadian cycle.

But one of the layers of the clock represents daylight.

The Circadian Clock has no relationship with the 'Circassian Circle'.

The Circassian Circle is a dance whose origin is possible in the Circassian people.

The Circassians are a people that was displaced during the conquest of the Caucasus in 1862 and still suffering the effects of the Circassian diaspora:

http://en.wikipedia.org/wiki/Circassian_diaspora

## Adding apples and oranges

nummolt

1

Educational app about adding apples and oranges.

To calculate the value of an apple and an orange from 2 purchases.

(Assuming that all apples are equal and that all oranges are equal)

About mental arithmetic with a pre-algebra tool, introducing the Gaussian elimination. ( Gauss - Jordan )

From http://www.nummolt.com/obbl/appleorange/index.html

nummolt - Obbl - Math Toys collection - Mathcats.

To calculate the value of an apple and an orange from 2 purchases.

(Assuming that all apples are equal and that all oranges are equal)

About mental arithmetic with a pre-algebra tool, introducing the Gaussian elimination. ( Gauss - Jordan )

From http://www.nummolt.com/obbl/appleorange/index.html

nummolt - Obbl - Math Toys collection - Mathcats.

MathTools reference:

http://mathforum.org/mathtools/tool/178345/

Algebra Linear Systems

Algebra II Solving systems of equations, Elimination

PreCalculus Solving systems of linear equations, Gauss-Jordan Method, determinants

We recommend the paid 'Apples and Oranges 1 Decimal':

http://play.google.com/store/apps/details?id=com.appleorange.firstdecimal

(http://mathforum.org/mathtools/tool/219536/)

Math 7: Linear relationships, Find slope, Slope-intercept form, Equation of the line, Rect coordinate geometry, First quadrant, Geometry in the plane

Algebra: Linear Equations, Slope Between Points, Finding Intercepts, Slope - Intercept Form, Point - Slope Form, Graphing, Parallel Lines, Perpendicular Lines, Linear Formulas, Analyzing Linear Data, Is It Linear?, Writing an Equation, Line of Best Fit, Linear Systems, Solve by graphing, Solve by substitution, Solve by combination, Inconsistent System, Applications

Algebra II: Solving systems of equations, Cramer's rule, Matrices, Elimination, Substitution

NOTE:

'Adding apples and oranges' app free, is a simplified version of the first part of the nummolt's paid app: 'Apples and oranges 1 decimal place'. (the Gauss-Jordan elimination)

All options "Apples and oranges first decimal":

( 1: Gauss-Jordan elimination; 2: Graphic; 3: Substitution; 4: Cramer's rule; 5: Inverse matrix )

Credits:

Feature graphic by: http://photo-lgz.blogspot.com/

## Adding unit fractions

nummolt

1

The app proposes 21 challenges to overcome.

Obtaining the proper fractions listed at the top of the application, adding two or three unit fractions.

Obtaining the proper fractions listed at the top of the application, adding two or three unit fractions.

Each proposed proper fraction has a variable number of solutions.

And different levels of difficulty

You can not repeat unit fractions with the same value.

In the app you'll find a button to delete all the solutions found in the current problem, and to start from scratch.

The littlest unit fraction used in this app is 1/28.

The program is designed to show the usefulness of the subtraction of fractions in solving such problems.

From www.nummolt.com

This is an evolution of the "Old Egyptian Fractions" made in collaboration with www.mathcats.com

Hint:

In the Rhind Mathematical Papyrus (RMP) in 1650 BC the scribe Ahmes copied the now-lost test from the reign of the king Amenemamhat III .

The first part of the papyrus is taken up by the 2/n table. The fractions 2/n for odd n ranging from 3 to 101 are expressed as sums of unit fractions.

In this app you can build some of the Ahmes decompositions ( 2/3 , 2/5, 2/7, 2/9 ) and the discarded ones by him also.

The app allow to decompose also: 3/4 , 3/5 , 4/5 , 5/6 , 3/7 , 4/7 , 5/7 , 3/8 , 5/8 , 7/8 , 4/9 , 5/9 , 7/9 , 8/9 , 3/10 , 7/10 , 9/10.

You can use the knowledge acquired solving the 2/n decompositions to solve the rest of the problems.

More: http://nummolt.blogspot.com/2014/12/adding-unit-fractions.html

Math Tools reference of this app:

http://mathforum.org/mathtools/tool/260740/

Courses:

Math 1, 2 and 3: Fractions

Math 4: Writing fractions, Equivalent fractions, Comparing and ordering, Simplifying fractions, Adding fractions, Subtracting fractions

Math 5, 6 and 7: Writing fractions, Equivalent fractions, Comparing & ordering, Simplifying fractions, Adding fractions, Subtracting fractions, Multiplying fractions, Dividing fractions

## How much pizza to order?

nummolt

1

Android version of the "How Much Pizza to order?

http://www.nummolt.com/obbl/howmuchpizza/index.html

http://www.nummolt.com/obbl/howmuchpizza/index.html

"How much pizza...?" About adding fractions: Working with Improper fractions and Mixed fractions. The program build the problem, and you can solve filling the textboxes containing question marks. There's a tool that helps you find the common denominator.

Inspired by the works of Cynthia Lanius ("Who wants pizza?")

Nummolt - OBBL Math Toys

http://www.nummolt.com/obbl/index.html

MathTools reference:

http://mathforum.org/mathtools/tool/186520/

Math 3 Equivalent fractions

Math 4 Equivalent fractions, Simplifying fractions, Adding fractions, Fractions <--> decimals

Math 5, 6, 7 Equivalent fractions, Simplifying fractions, Adding fractions, Multiplying fractions, Writing decimals, Fractions <--> decimals

For more difficult exercises on fractions, we recommend:

Mathcats: "Old Egyptian Fractions":

http://play.google.com/store/apps/details?id=mathcats.oldegyptian.fractions

## Touch Pythagoras

nummolt

1

Touch Pythagoras:

The Pythagorean Theorem Interactive: a^2 + b^2 = c^2

The Pythagorean Theorem Interactive: a^2 + b^2 = c^2

App:

You can change the lengths of the legs (dragging).

You can change the length of the hypotenuse with two fingers.

You can zoom (pinch zoom) and rotate the figure (dragging).

There are 6 ways to view the Pythagorean theorem.

- Unit surfaces.

- Two equivalent square containing the same surface.

- The square for each leg in the square of the hypotenuse (Euclid)

- Pingi - Dudeney proof.

- Da Vinci.

- Bhaskara reasoning.

You can change the precision of the lengths. (In the contextual menu)

This application is also a small laboratory to investigate about the Pythagorean Theorem:

For example, you can experiment easily, looking for the exact solutions of the Pythagorean Theorem:

3² + 4² = 5² is not the only exact solution:

Below 21, there are 3 primitive triples:

3² + 4² = 5²

5² + 12² = 13²

6² + 8² = 10² (Not a true primitive result: Multiple of 3,4,5)

8² + 15² = 17²

9² + 12² = 15² (Not a true primitive result: Multiple of 3,4,5)

12² + 16² = 20² (Not a true primitive result: Multiple of 3,4,5)

Likewise it is also possible to find the solutions below 31 (11 solutions in all: but only 5 primitives)

Or solutions below 101 (52 solutions in all: but only 16 primitives)

More about this: Pythagorean triples: http://en.wikipedia.org/wiki/Pythagorean_triples

Touch Math Apps:

http://www.nummolt.com

MathTools reference of this app:

http://mathforum.org/mathtools/tool/206418/

Math 4 Triangles

Math 6 Geometry in the plane, Triangles, Pythagorean theorem

Math 7 Geometry in the plane, Triangles, Pythagorean theorem, Quadrilateral properties

Geometry Triangles, Right, Right Triangles, Special right triangle, Pythagorean theorem, Trigonometry

Algebra Exponents

Algebra II General

Trigonometry Right Triangles

From here we recommend the web page about the Pythagorean Theorem of Alexander Bogomolny:

http://www.cut-the-knot.org/pythagoras/index.shtml

(Shows 101 proofs of the Pythagorean Theorem)

## 9 digits

nummolt

1

The game is about to find solutions ordering the digits from 1 to 9 in a square of 3 * 3 where the sum of the numbers of the two top rows is equal to the bottom row.

This program is aimed at reflecting on the addition. The goal is to find results that meet the primary condition. We must be aware that after obtaining a correct result can be achieved more easily results having in mind the properties of the sum.

Interaction:

To swap two digits must be done tap on each digit, then the digits change the color, and the exchange occurs.

From:

http://www.nummolt.com/obbl/ninedigits/ninedigitsbasic.html

nummolt - Obbl - Math Toys collection - Mathcats.

Ninedigits has 336 solutions. If the program would be easy for someone, then the goal could be to find valid solutions in which a lady could travel chess boxes 1 to 9 making right moves to this tab. According to our analysis, there are 3 solutions of this type. You can also look under the same condition, but with the tower of chess. This combination of conditions has only one solution. The program clearly shows the production of these special results.

As a safety mechanism, the delete button only works when the program displays a correct solution of the problem.

Registered in Math Tools (MathForum):

http://mathforum.org/mathtools/tool/234619/

Classified for courses:

Math 2 Addition

Math 3 Addition, Mental math

Math 4 Addition, Mental math

Math 5 Addition, Mental math, Commutative

Math 6 Addition, Mental math, Commutative

Math 7 Mental math, Commutative

Aligned with Common Core Math:

Grade 3 and up:

Grade 3 » Number & Operations in Base Ten

CCSS.Math.Content.3.NBT.A.2

Fluently add and subtract within 1000 using strategies and algorithms based on place value, properties of operations, and/or the relationship between addition and subtraction.

Origin of the game:

The ninedigits is based on an idea described in the book: "New Mathematical Diversions" by Martin Gardner published in 1966.

## Touch Natural Numbers

nummolt

1

Small laboratory of Natural Numbers:

The Prime numbers are the building blocks of the numbers.

With this app you can:

Analyze the factors of a Composite number.

( Prime factorization of all the composite numbers between 1 and 28181 ).

Build a Composite number from its factors. (multiplication and division of Natural Numbers)

Localize or select a number in the Ulam Spiral.

(Only the Prime Numbers have a color in this spiral).

Verify all the possible products between Primes in a composite number with the Parabolic Sieve (Yuri Matiyasevich & Boris Stechkin).

Analyze or build a number with the Place Value activity (Addition and Subtraction of Natural Numbers)

Understand the Modulo of a number.

Know about the polygonal numbers and the numbers as the sum of two prime numbers, and as the sum of three Prime Numbers.

The Prime numbers are the building blocks of the numbers.

With this app you can:

Analyze the factors of a Composite number.

( Prime factorization of all the composite numbers between 1 and 28181 ).

Build a Composite number from its factors. (multiplication and division of Natural Numbers)

Localize or select a number in the Ulam Spiral.

(Only the Prime Numbers have a color in this spiral).

Verify all the possible products between Primes in a composite number with the Parabolic Sieve (Yuri Matiyasevich & Boris Stechkin).

Analyze or build a number with the Place Value activity (Addition and Subtraction of Natural Numbers)

Understand the Modulo of a number.

Know about the polygonal numbers and the numbers as the sum of two prime numbers, and as the sum of three Prime Numbers.

What is all this about? Read the nummolt blog post:

http://nummolt.blogspot.com.es/2014/06/touch-natural-numbers.html

Touch Math Apps:

http://www.nummolt.com

Registered at MathTools ( MathForum )

http://mathforum.org/mathtools/tool/240793/

Courses:

* Math 1 - Place value

* Math 2 - Place value

* Math 3 - Addition, Subtraction, Multiplication, Division, Whole numbers, Place value, Prime, Composite, Factor, Prime factorization, Divisibility tests, Multiple

* Math 4 - Addition, Subtraction, Multiplication, Division, Whole numbers, Place value, Prime, Composite, Factor, Prime factorization, Divisibility tests, Multiple

* Math 5 - Addition, Subtraction, Multiplication, Division, Whole numbers, Properties of numbers, Prime, Composite, Factor, Prime factorization, Divisibility tests, Multiple

* Math 6 - Addition, Subtraction, Multiplication, Division, Properties of numbers, Exponents, Prime, Composite, Factor, Prime factorization, Divisibility tests, Multiple

* Math 7 - Properties of numbers, Roots/radicals, Writing square roots, Prime, Composite, Factor, Prime factorization, Multiple

## Adding unit fractions +

nummolt

1

The app proposes 31 challenges to overcome.

Build the proper fractions listed at the top of the application, adding two, three or four unit fractions.

Build the proper fractions listed at the top of the application, adding two, three or four unit fractions.

Each proposed proper faction has a variable number of solutions.

And different levels of difficulty

You can not repeat unit fractions with the same value.

In the app you'll find a button to delete all the solutions found in the current problem, and to start from scratch.

The littlest unit fraction used in this app is 1/66.

The program is designed to show the usefulness of the subtraction of fractions in solving such problems.

From www.nummolt.com

This is an evolution of the "Old Egyptian Fractions" made in collaboration with www.mathcats.com

Hint:

In the Rhind Mathematical Papyrus (RMP) in 1650 BC the scribe Ahmes copied the now-lost test from the reign of the king Amenemamhat III .

The first part of the papyrus is taken up by the 2/n table. The fractions 2/n for odd n ranging from 3 to 101 are expressed as sums of unit fractions.

In this app you can build some of the Ahmes decompositions ( 2/3 , 2/5, 2/7, 2/9, 2/11 ) and the discarded ones by him also.

The app allow to decompose also: 3/4 , 3/5 , 4/5 , 5/6 , 3/7 , 4/7 , 5/7 , 6/7 , 3/8 , 5/8 , 7/8 , 4/9 , 5/9 , 7/9 , 8/9 , 3/10 , 7/10 , 9/10, 3/11, 4/11, 5/11, 6/11, 7/11, 8/11, 9/11, and 10/11.

You can use the knowledge acquired solving the 2/n decompositions to solve the rest of the problems.

The app warns of obtaining the best solution (the one with the lowest denominators)

If it's one of the problems appearing in the Rhind Mathematical Papyrus table, the app warns of coincidence with the solution written in the Rhind 2/n table.

More: http://nummolt.blogspot.com/2014/12/adding-unit-fractions.html

## Jujol arq.

nummolt

1

Review and locate the Josep Maria Jujol main architectural works:

Casa Bofarull Els Pallaresos.

Església del Sagrat Cor de Vistabella

Teatre del Patronat Obrer de Tarragona

Casa Ximenis de Tarragona

Can Negre de Sant Joan Despí

Casa Sansalvador de Barcelona

Casa Planells de Barcelona

......

He worked with Antoni Gaudí on many of his most famous works: Casa Batlló (facade cladding), Casa Milà (balcony railings and ceiling), Park Güell (Roofing and continuous bench)

Casa Bofarull Els Pallaresos.

Església del Sagrat Cor de Vistabella

Teatre del Patronat Obrer de Tarragona

Casa Ximenis de Tarragona

Can Negre de Sant Joan Despí

Casa Sansalvador de Barcelona

Casa Planells de Barcelona

......

He worked with Antoni Gaudí on many of his most famous works: Casa Batlló (facade cladding), Casa Milà (balcony railings and ceiling), Park Güell (Roofing and continuous bench)

## Apples and oranges 1 decimal

nummolt

1

Apples & Oranges - Algebra

Adding Apples and Oranges Version with 1 decimal

Adding Apples and Oranges Version with 1 decimal

This new application is a basic tool to learn algebra.

Trying solving a system of linear equations with two equations and two unknown variables. (Two purchases)

Based on the same problem seen at the free "Adding Apples and Oranges." (https://play.google.com/store/apps/details?id=com.appleorange.addingapplesandoranges) where only used integers.

Now, this new program works externally with a decimal.

It contains:

. A button that generates new questions ("two new purchases of fruits").

. Two drop-downs to select a solution and a button to verify: The verification button checks the solution, and adds it to the list of the session.

You can edit the statements. The program checks if the determinant of the proposed statement is nonzero.

. The 5 tools to help resolve the problem:

* Tool 1: Gauss-Jordan elimination:

The two equations are represented as two purchases of fruits.

Contains tools to add one column to another, multiply, divide and change the sign for to get to have one apple on a side and and an orange at the other.

The result of the two additions are the values of apple and orange.

* Tool 2: Graphic:

Contains a graphic frame and 2 drop-downs to find the solution, using the method essay / error.

The problem posed is a linear system of equations, so the results must be ever into two lines that intersect.

To get the answer, one should find this point.

You can also click directly on the chart.

The graph is divided by the diagonal.

Below the diagonal, apple values are entered, for to get the values of the orange.

Above the diagonal, one enters the price of the orange.

The meeting point of the two lines is represented by a yellow dot.

* Tool 3: Two weighing scales:

Shows two weighing balances. On the left, due to its drop-down, which determines the value proposed for apples: results gives the price of oranges in terms of the two equations.

The right hand scale gives the results from the proposed price for oranges.

When a scale is balanced, gives the results of both the price of the apples and oranges.

* Tool 4: Cramer's rule:

This tool solves the problem at once.

Contrary to what happens in other tools, here we have to manually enter the data of the problem. The two equations (two purchases) are represented in horizontal rows.

If you have not entered data, the tool warns that you can not solve the problem.

It can also warn when the determinant is zero:

The determinant is zero when the two lines that we saw in the graphical tool, are not crossing. This happens when they are parallel. And the lines are parallel when a purchase (equation) is linear function of the other. (eg 1 A + 2 O= n1 and 2 A + 4 O = n2)

The program automatically never generates such problems.

* Tool 5: Inverse matrix:

The tool represents the terms of the equation automatically and in landscape format (each purchase is a row)

The resolution tool there are the terms of the two equations on the left and the identity matrix at right.

The objective is to calculate the inverse matrix.

This is achieved by operating the rows, until the data from the equations (on the left) become the identity matrix.

At this time to the right we have the inverse matrix.

The multiplication of the results vector by the inverse matrix gives the solution.

This program shows rounded numbers.

Internally works with all decimals needed.

If you try to do these calculations with a calculator, you'll see that this program displays the friendly face of algebra.

Mathforum MathTools Reference:

http://mathforum.org/mathtools/tool/219536/

Math 7: Linear relationships, Find slope, Slope-intercept form, Equation of the line, Rect coordinate geometry, First quadrant, Geometry in the plane

Algebra II: Solving systems of equations, Cramer's rule, Matrices, Elimination, Substitution

Buying this program will help develop new nummolt apps.

Credits:

Feature graphic by: http://photo-lgz.blogspot.com/