X² Challenge

Cogito55

About this game

X-Squared Challenge is a math app that challenges players to build equations — not just solve them. Using integers, operators, parentheses, and exponents, players construct expressions that equal a target number while following the order of operations (PEMDAS).

Three ways to play:

LEARN — Pick one operation and build a two-card equation. The gentlest introduction, with no login and no scoring.

PRACTICE — Three or four cards, every integer available, no pressure and no score.

COMPETE — Level 4 and Level 6 puzzles that earn points, with streaks and a score that follows you across devices.

This game is unique in that it requires creative reasoning — players must create equations rather than simply solve them. The game promotes enhanced learning for students and others practicing their understanding of the order of operations and math facts. Anyone who plays, regardless of their current level of mathematics, will improve their basic math skills.

X-Squared Challenge was derived from a patented product called the X-Squared Math Card Deck, produced by Cognitive Card Games LLC. That order of operations deck is the only one available to the public with two important characteristics: it is both simple and complete. The elements are easy to use and understand in creating equations that conform to the rules of the order of operations. It is complete in that it includes all elements of PEMDAS: parentheses cards, exponent cards, multiplication, division, addition, and subtraction cards. The parentheses and exponent cards are transparent so they can overlay integer cards. The app incorporates all of the characteristics of the card deck.

What’s new

New Learn mode — pick one operation, then build a two-card equation to hit the target. The gentlest way into the game yet, with no login and no scoring.

The three modes are now Learn, Practice, and Compete, matching the website.

Also fixed:
• Answers no longer show a long string of decimal places
• Dividing by zero now reads as "Undefined" instead of "Infinity"
• The About screen shows the correct app version