# Sumday: Mental Math Practice — Arithmetic & Brain Training

> Arithmetic & Brain Training (iPhone/iPad app by TON CO., LTD..)

- Source: https://appshunter.io/ios/app/sumday-mental-math-practice/id6802302480 (this page in markdown: same URL + `.md`)
- Developer: [TON CO., LTD.](https://appshunter.io/developer/6796677381)
- Category: Education, Utilities
- Price: Free with in-app purchases
- Age rating: 4+
- Requires: iOS 15.0 · 34 MB
- Languages: American English, Japanese, Korean
- Released: 2026-10-02
- Data updated: 2026-10-12
- User reviews in markdown: https://appshunter.io/ios/app/sumday-mental-math-practice/id6802302480/reviews.md

## What is Sumday?

Five minutes a day to get your mental math back.
Sumday is a quiet daily routine for adults: real arithmetic, not puzzles, that keeps your number sense sharp.

The more we rely on calculators and spreadsheets, the slower the math in our head gets. Sumday wakes it up with one short set a day that mixes addition, subtraction, multiplication, division, percentages and estimation. Learn one practical math trick a day, the kind school never taught you, and feel your speed come back.

WHO IT'S FOR
• Adults who feel their mental math isn't what it used to be
• Anyone preparing for aptitude or job tests with timed number questions
• People who want to split a bill, work out a discount or estimate a total in seconds
• Anyone looking for light daily brain training

HOW IT WORKS
1. Solve today's set of 20 questions. Five minutes is enough.
2. Check your results: accuracy and response time, compared with yesterday.
3. Unlock today's technique card and use it in tomorrow's set.
4. Come back tomorrow. A daily reminder keeps your streak going.

FEATURES
• Today's set: 20 mixed arithmetic questions across 7 types: addition, subtraction, multiplication, division, percentages, estimation and everyday math
• Adaptive difficulty: questions get harder as you improve and ease off when you get stuck (12 levels)
• Daily technique cards: 30 mental math tricks, from rounding shortcuts to quick percentages
• Results report: accuracy, average response time and change since yesterday on one screen
• Progress charts: daily and weekly trends in accuracy and speed
• Streaks and a gentle daily reminder

NO ACCOUNT, NO SERVER
No sign-up needed. Your records stay on your device, and it works in airplane mode.

PREMIUM (OPTIONAL)
A one-time purchase removes ads and unlocks 3 practice modes (estimation, percentages, everyday math), Challenge mode (endless survival with 3 lives), detailed statistics and all 30 technique cards. No subscription.

Available in English, Korean and Japanese.

Start your five minutes of math practice today.

## Pricing and in-app purchases

Base price: Free.

**One-time purchases**

| Purchase | Price | Type |
| --- | --- | --- |
| Sumday Premium | $3.99 | one-time |



## Version history (last 5 releases)

### 1.2.0 — 2026-10-03

Sumday now speaks English and Japanese.
• The app follows your device language (English, Japanese or Korean; other languages show English).
• Polished technique cards and question wording.
• Fixed chart labels being cut off at the largest text size.
• Added Ad privacy choices to Settings where consent is required.

### 1.1.2 — 2026-09-17

안정성을 다듬고 내부 구조를 정리했어요.
· 앱 사용 방법과 기능은 그대로예요.

### 1.1.1 — 2026-09-08

프리미엄 구매 복원 시 안내가 잘못 표시될 수 있는 문제를 수정했어요.
· 구매 내역이 있는데도 "복원할 구매가 없다"고 안내되던 경우를 바로잡았습니다.
· 복원 응답이 늦거나 끊기면 오류로 안내하고 다시 시도할 수 있습니다.

### 1.1.0 — 2026-09-05

새로운 얼굴로 돌아왔어요.
· 차분한 회색 바탕과 또렷한 검은 글자로 화면을 정리했습니다. 계산에만 집중할 수 있게요.
· 파란 구름 친구가 연속 기록과 도전 라이프를 지켜줍니다.
· 앱 아이콘과 시작 화면도 새 디자인으로 바뀌었습니다.
· 하단 메뉴를 아이콘만 남겨 더 가볍게 만들었습니다.
문제 생성·난이도·기록 등 학습 기능은 그대로입니다.

### 1.0.1 — 2026-09-03

· 스토어 정보 갱신 (앱 이름·소개 문구 개선)
· 안정성 개선

## More apps by TON CO., LTD.

- [Coatly: Paint Calculator](https://appshunter.io/ios/app/coatly-paint-calculator/id6796677379)
- [Mudly: Concrete Calculator](https://appshunter.io/ios/app/mudly-concrete-calculator/id6798218661)
- [Tapday: Reaction Time Test](https://appshunter.io/ios/app/tapday-reaction-time-test/id6811889860)

All apps by TON CO., LTD.: https://appshunter.io/developer/6796677381

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*Data collected daily from the US App Store and indexed by [AppsHunter](https://appshunter.io/). User reviews are verbatim App Store reviews. Ratings, prices and chart positions refresh continuously; this snapshot is from 2026-10-12.*