무한숫자 - 7단

This is a game where you have to touch the numbers 7, 14, and 21 as quickly as possible in 30 seconds.

It requires a high level of concentration and agility, and is very helpful for brain activity.

If you want to teach parents and children how to use quick brains, it can be used as a fun and competitive learning tool.

It can be done in just 30 seconds at a time to kill time, so anyone can use it easily and simply.