百マス計算脳トレ無料アプリ is an educational game available on Android. Developed by ano_game, this app offers calculation challenges in fields of 10, 50, and 100 squares. While it doesn't include division, it provides a casual brain training experience.

Surprisingly, simple calculations can be quite enjoyable. The 10-square calculations, for instance, can be completed in no time. Despite displaying ads, the app is completely free.

The app offers different levels of difficulty based on response speed, ranging from "Good" to "Great" to "Excellent." However, it's unclear how many users are able to reach the "Excellent" level.

Overall, 百マス計算脳トレ無料アプリ is a free educational game that offers simple calculation challenges in various-sized fields. It's a great option for those looking for a casual brain training experience on their Android device.