Abacus Lesson vs Flash
Price, ratings, monetisation and update history for both apps, side by side — with what reviewers say about each.
Abacus Lesson
Learn the simple and fast method of division using an abacus. This app focuses on developing mental calculation skills by leveraging the abacus technique. It's recommended to master addition, subtraction, and multiplication with an abacus first.
- Learn abacus division techniques
- Develop mental calculation skills
- Focus on Soroban method
- Step-by-step division instruction
- Builds on addition, subtraction, multiplication
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An abacus is named "Soroban" in Japan. Do you know what an abacus is? The abacus is very simple calculator used in China, Japan, Korea and so on. Some people may say "Isn't it an unnecessary tool if you have a calculator such as a smartphone?". Answer would be "No". The biggest difference between electric calculators and the abacus is whether you need to hold it in your hand when calculating. Because of its simplicity, you will be able to easily use the abacus in your mind. In the app, we will explain simple and fast method of the division using the abacus. To learn division, it is essential to be able to add, sub, and multiplication with an abacus. If you are new to them, we recommend that you learn addition subtraction multiplication with the app in my app list first. This app will give you the skill of calculation of division.
Flash
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Train your mental arithmetic with numbers that flash one at a time. Watch the sequence, add it in your head, and enter the total before the next round. Flash keeps practice simple: • Choose 1–7 digits and 2–500 numbers. • Set the display speed from 0.1 to 3.0 seconds. • Practice 1–999 rounds or keep going in Infinite mode. • Turn answer input and automatic continuation on or off. • Choose a light or blue background. • Use sound, haptic, or both for feedback. • Save your favorite settings as presets. • Check accuracy, response time, streaks, and total training time. • Review the exact number sequence for each round and retry mistakes. Use it for a quick session or a longer challenge. Flash gives you a clear way to practice at your own pace.
Screenshots
Verdict
The clearest difference is in-app purchases: Flash at none against Abacus Lesson's 3. Flash also leads on ads (none vs shown). Abacus Lesson's advantage is update cadence (monthly vs every 4 months) and iOS requirement (11.0 vs 17.0). 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. Abacus Lesson sells 3 one-off in-app purchases. Flash asks for nothing beyond the download.
Abacus Lesson ships an update monthly, Flash every 4 months. The most recent releases landed on September 21, 2026 and September 18, 2026 respectively.
| Parameter | Abacus Lesson | Flash |
|---|---|---|
| Price | Free | Free |
| Rating | 5.0 (8 ratings) — better | — |
| Positive reviews | 100.0% of reviews | — |
| Number of ratings | 8 — better | — |
| Update frequency | Monthly — better | Every 4 months |
| Ads | Yes | No — better |
| In-app purchases | Yes | No — better |
| Monetization | Free with in-app purchases | — |
| Devices | iPhone, iPad, iPod — better | iPhone, iPad |
| Requires iOS | 11.0 — better | 17.0 |
| Further details — not scored | ||
| Size | 132 MB | 16 MB |
| Age rating | 4+ | 4+ |
| Developer | Hirokazu Komatsu | yeeun seo |
In-app purchases
Abacus Lesson
- Donation Lv1 for hiding Ad$1.99
- Donation Lv2 for hiding Ad$3.99
- Donation Lv3 for hiding Ad$8.99
Flash
No in-app purchases








