Simaple math practice

This is a simple math practice app for children .

There is no time limit.
There is no limitation on the number of questions.

Form of the problem is " fill-in-the-blank question" ,
Hole will be change at random .

Problem is created at random.

By changing the number of digits to be used in the setting screen ,
It is possible to change the difficulty of the problem .

[Notes ]
A problem of subtraction is answer is zero or more all .
A problem of the division will be questions an divisible all .