Children count and learn

I have created this application to learn my son how to count.
Children learn to count and get sweets for their answers.
The author of pictures is my 5 years old son, who counts to achieve sweets.

Three levels:
Easy Level + and - small numbers.
Medium Level +, - and * bigger numbers.
Hard Level +,-,* and : the biggest numbers.

It's free game with three levels of counting.