About this app
I wanted to play "Oni Keisan" on my iPhone! That's why I created this N-Back brain training app. What is this training? Solve calculations while remembering the answers from a few questions back. Juggling "memorizing" and "calculating" at the same time gives your brain a real workout. Features ◆ Two Input Modes - Tap Mode: Quickly tap the answer - Handwriting Mode: Write numbers directly ◆ Build Daily Habits - Set daily play goals - Track your streak - Record how you're feeling today ◆ Track Your Progress - Accuracy trends - Level-up history - Play history ◆ Customize Your Way - Adjust question count & time limits - 3 color themes - iPhone & iPad support Perfect For - Those who want to play Oni Keisan without a dedicated game console - Anyone looking for a quick mental exercise - People who want to build a daily habit Just 5 minutes a day. A casual brain training experience.
Latest release
What’s New
ver3.1.1 - dark mode - fix layout
Audience growth
Ratings growth
Baseline captured. Growth appears after the crawler observes a changed rating count.
Momentum comes from crawler snapshots for the tracked storefront. “Viral growth signal” means unusually fast recent rating gains; it is an indicator, not download data.
Price tracking
Price intelligence
First snapshot captured. The trend line starts after the next crawler price observation.
- First observed Aug 20, 2026 · 9:46 PM Free
Screenshots
