脳年齢測定器 is an Android app that allows you to measure your brain age by answering a series of questions. The app offers four types of challenging games that aim to improve your accuracy, memory, and reflexes.

The first game tests your memory by displaying numbers that you need to remember. The second game challenges your reflexes by requiring you to shake your Android device in the direction shown on the screen. The third game is a subtraction game where you have to continuously subtract numbers until you reach zero. Finally, the fourth game tests your quick thinking and button pressing skills as you tap on 20 buttons in ascending numerical order.

Please note that when playing the games, it is important not to shake your Android device too forcefully. Additionally, it's important to remember that the brain age measured by the app serves as an approximate indicator and should be taken with a grain of salt.