MathGrid 100 vs Study Clock Timer
Price, ratings, monetisation and update history for both apps, side by side — with what reviewers say about each.
MathGrid 100
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MathGrid 100 — Photo-graded math drills for daily mental math practice. Known in Japan as "Hyakumasu Keisan" (百マス計算 / 100-square calculation), this classic drill is a proven method for building mental math fluency, recommended by Japanese educators such as Hideo Kageyama. MathGrid 100 brings this method to your iPhone with AI-powered photo grading: just snap a picture of the completed worksheet and get an instant score. 【Features】 * Camera-based instant grading — no typing required * Supports addition and multiplication * 9×9 (multiplication) and 10×10 grids * Review and manually edit each cell if needed * Saves up to 20 sessions in history * Points, levels, and badges to keep kids motivated * Daily streak tracking * Up to 4 separate child profiles with individual progress 【Great for】 * Parents tired of manually grading drill sheets * Tracking your child's daily practice * Gamifying repetitive practice to keep kids engaged * Supplementing Kumon, abacus class, or other math curricula ※ Internet connection required (handwriting recognition runs in the cloud). ※ This app shows a persistent banner ad and an interstitial ad after every few gradings.
Study Clock Timer
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Study Clock Timer is a gentle clock timer that helps you see how long you will study and when you can take a break. Instead of setting time only with numbers, you can move the clock hands and see study time and break time as colored areas on the clock. ■ Study time shown on a clock ・Shows the current time on an analog clock ・Set how many minutes to focus by moving the hand ・Shows study time and break time with colors inside the clock ■ Settings families can decide together ・Short starter settings for first-time users ・Recommended settings close to the classic Pomodoro technique ・Shows the flow of study, break, study, break, study, and a longer break ■ Progress history ・See study totals for today, the last 7 days, and this month ・Records are stored locally on the device Study Clock Timer uses simple wording and a friendly design so anyone can start small and keep going.
Screenshots
Verdict
The clearest difference is in-app purchases: MathGrid 100 at none against Study Clock Timer's 1. MathGrid 100 also leads on iOS requirement (15.1 vs 17.0). Study Clock Timer's advantage is ads (none vs shown) and update cadence (every 3 days vs every 3 weeks). On price and device support there is nothing between them.
Scored on Price · Rating · Positive reviews · Number of ratings · Update frequency · Ads · In-app purchases · Monetization · Best chart rank · Devices · Requires iOS
Both are free to download. Study Clock Timer sells 1 one-off in-app purchase. MathGrid 100 asks for nothing beyond the download.
MathGrid 100 ships an update every 3 weeks, Study Clock Timer every 3 days. The most recent releases landed on September 29, 2026 and September 18, 2026 respectively.
| Parameter | MathGrid 100 | Study Clock Timer |
|---|---|---|
| Price | Free | Free |
| Update frequency | Every 3 weeks | Every 3 days — better |
| Ads | Yes | No — better |
| In-app purchases | No — better | Yes |
| Devices | iPhone, iPod | iPhone, iPad |
| Requires iOS | 15.1 — better | 17.0 |
| Further details — not scored | ||
| Size | 40 MB | 5 MB |
| Age rating | 4+ | 4+ |
| Developer | Hiroyuki Ishikawa | Tatsuya Kawasaki |
In-app purchases
MathGrid 100
No in-app purchases
Study Clock Timer
- Buy me a drink$2.99
Questions
Is MathGrid 100 free?
Is Study Clock Timer free?
Do MathGrid 100 or Study Clock Timer have ads?
Which is updated more often, MathGrid 100 or Study Clock Timer?
Other comparisons
