The foundation of Dr Kageyama's Maths Training is 100 square calculations a method conceived by Kageyama Hidea, a Japanese elementary school principal. The DS is held side ways like a book and all answers are written using the stylus. The key principal of the software is repetition which according to Kageyama stimulates the brain. The main exercise 100 cells maths, consists of 100 hundred simple maths problems combined into a 10 by 10 grid using the numbers at the top and side of the grid. There are however many other exercises, ranging from simple one digit math problems to slightly more complex three digit challenges.