나만의 진정한 AI 오답노트, OnO

기승민

About this app

This is a learning app that allows you to complete an error notebook with just a single photo, leading to skill improvement through AI analysis and review notifications. If you have ever wanted to organize your incorrect answers but gave up because it was too cumbersome, OnO is the perfect fit for you. It can be used for any subject, from the CSAT and school grades to certifications and foreign language studies.

1. Complete an Error Notebook with a Single Photo

Simply take a picture with your camera or select one from your gallery to instantly create an error notebook. You can attach multiple images of both the question and the answer, and organize sources, notes, solution dates, and tags all at once. When you upload an image, the AI ​​automatically recommends source titles and related tags. There is also a feature to batch register up to 20 questions at once, making it particularly useful for reviewing everything in a rush immediately after an exam. You can also capture your organized error notebook as an image card and share it on social media.

2. Three Templates to Suit Your Purpose

You can choose one of three templates depending on the subject and situation.

▸ Memorization King Template — This is the basic format optimized for quick registration. Recommended for memorization subjects or simple problems.

▸ Problem Solving King Template — AI automatically erases blue handwriting on the problem sheet to keep it neat and tidy. Well-suited for Korean, English, and Social Studies.

▸ Guide Template — Provides handwriting removal as well as AI error analysis. Most powerful for Math and Science problems.

You can select each template upon registration and change it later in the editing screen.

3. Identifying Weaknesses with AI Error Analysis

For problems registered with the Guide Template, AI automatically analyzes which concepts are lacking based on the curriculum. It goes beyond simply collecting incorrect answers to clearly identify "why you got them wrong." The analysis starts automatically after uploading an image and can be viewed immediately upon completion. Analyzed weak concepts can also be collected separately in the learning report.

4. Re-solve Problems Directly Within the App

You can write directly by hand within the app when re-solving problems. It supports 12 color palettes, adjustable pen and eraser thickness, pinch zoom, and panning, and is compatible with Apple Pencil. You can solve problems by flipping through multiple problem images in sequence, and the time taken is automatically measured by a timer. If you are in an environment where taking notes is difficult, you can also choose to solve the problems on the spot and upload a photo. Once you finish solving, your review record includes whether the answer is correct, the time taken, an improvement checklist (avoiding previous mistakes, discovering new solutions, clear understanding of concepts, and time reduction), and notes. History accumulates for each problem, showing where you made mistakes previously and how your time was reduced.

5. Review Sets and Custom Notifications

You can create your own review sets by selecting the problems you want. You can filter problems by folder, tag, or title to select multiple items at once, and decorate set thumbnails with custom emojis. If you set the notification frequency (daily or weekly) for each set, push notifications will remind you to review just when you might forget. Once you complete a review, you can leave a record of your mood for the day using an emoji. You can also check the list of problems requiring review today, based on the server, directly on the home screen.

6. Systematic Classification with Folders and Tags

You can create as many subfolders as you want to organize by subject or unit. Decorate folder icons with 31 custom emojis and freely move folders and incorrect answer notes using drag-and-drop. You can also select multiple items at once using the long-term tab to move or delete them, or drop them into the trash can that appears at the bottom of the screen while dragging to delete them immediately. You can create your own tags to classify problems and quickly find specific questions by tag or title. The AI ​​automatically recommends relevant tags based on the problem image, making classification much easier.

7. Study Calendar and Continuous Streaks

Study days are recorded on the calendar, and continuous study days (streaks) accumulate. Just like GitHub's "grass," colors darken according to study intensity, allowing you to see at a glance whether you have been studying consistently. Tapping a date summarizes the content reviewed that day, the number of incorrect answers registered, and the total study time. You can receive commemorative badges when you achieve 7-day, 30-day, and 100-day milestones. You can see your current consecutive study days, longest record, and study days for this month at a glance on My Page. There is also a study diary feature where you can leave short notes and daily emotion emojis for each date.

8. Study Reports and Achievement Sharing

It analyzes review counts, average correct answer rates, daily review trends, and weak concepts by weekly, monthly, and overall period. You can identify which subjects require more focus through numerical data. You can also create card images of this week's achievements to share on social media. You can even capture images of your incorrect answer notes in the app's design card format to share with friends.

9. Characters and Themes That Grow as You Study

You can build levels in four areas: attendance, writing incorrect answers, problem solving, and set reviews. The levels in each area are added together to increase your total study level, and as your level rises, the frog character's appearance changes step by step. Each time you level up, one of the 24 app theme colors is unlocked. You can check your current progress at a glance using the level card and donut progress bar on My Page. It is designed so that studying itself becomes the reward.

10. Study Together in Social Study Rooms

Study rooms are helpful when you start to get lazy while studying alone. You can generate an invitation code and easily share it using the system's sharing function. The room host is responsible for managing members and creating challenges, and can freely set the room name and thumbnail.

▸ Weekly Ranking — Members are ranked based on the number of problems registered this week. If you set a personal weekly goal, your progress is displayed on the ranking card.

▸ Activity Feed — You can check members' learning events (problem registration, review completion, level up, challenge achievement, etc.) in real-time and react with emojis (🔥👍🎉).

▸ Problem Sharing — You can upload your incorrect answer notes to the room, add comments, or exchange comments and emoji reactions.

▸ Group Challenge — Boost mutual motivation with three types of challenges: individual goal achievement, member aggregate, and continuous streak. ▸ Weekly Report — Every week, the learning status of the entire study room is automatically summarized and shared with all members.

11. Easy for First-Time Users — Interactive Tutorial

When you first launch the app, an interactive tutorial begins right on the screen, allowing you to follow along directly. It guides you through key functions step-by-step, from creating folders and review sets to entering the study room and checking learning reports. You can rewatch the tutorial at any time in the settings.

Recommended for:

▸ Those who want to create error notebooks but give up every time because it's too much of a hassle

▸ Those who don't know which concepts they are weak in even after organizing incorrect answers

▸ Those who repeat the same mistakes because they miss review timing

▸ Those who lose motivation when studying alone

▸ Those who want to manage their study records smartly

▸ Those who want to be motivated together in a study group

▸ Those who want to visually track their study habits and maintain consistency

It supports Google, Apple, and Kakao logins, and you can try it out in Guest Mode without logging in. It supports both iOS and Android and provides a responsive UI optimized for both phones and tablets. On tablets, the layout is automatically adjusted to fit the screen, such as displaying the challenge list in two columns.

If you have any feedback or issues, please let us know via [Leave Feedback] in the app settings, and we will address them promptly.

What’s new

1. 홈 화면 위젯 추가
- 학습 기록과 오늘 복습할 문제를 홈 화면에서 바로 볼 수 있어요.

2. 추천 복습 개선
- 밀린 일수와 남은 정답 수가 보이고, 다음 문제를 바로 이어 풀 수 있어요.

3. 문제 풀이와 복습 기록
- 필기가 부드러워지고 연습장과 사진 비교가 생겼어요.
- 다시 풀기 옆 화살표로 이전, 다음 문제로 넘어갈 수 있어요.

4. 복습 세트 개선
- 문제를 바로 넣고 빼고, 틀린 문제만 다시 복습할 수 있어요.

5. 오답노트 작성과 관리
- 최근 등록순 정렬, 메모 바로 쓰기, 지운 뒤 되돌리기를 더했어요.

6. 화면과 사용성 개선
- 태블릿 두 줄 화면을 더하고 앱 전반의 문구와 디자인을 다듬었어요.