Math Brain Training will help you to exercise your brain.

Numbers are moving to make simple math problems of addition, subtraction, or multiplication.
You will calculate and input the answer.
When you chose hard mode, you have to remember former problems and input the answer of them. (This is called "N-back task" )

These math problems are easy, however, you have to predict the destination of moving numbers and remember former problems.
It will help you to use various part of your brain.
Especially, N-back task is said to be good for "working memory."
Working memory is a very important part of brain. For example, weak working memory is said to be linked to ADHD or ADD.