Train Your Brain - arithmetic

In this program you can choose one of four arithmatic operations (addition , subtraction , devision , multiplication). You will find a 90 seconds timer and four answers. By selection of correct answer your score will increase. After timer ends,your score , question numbers and grade will be displayed.
Your grade depends on the number of correct answers of answered questions.
Excellent grade appers if question numbers is greater than 30 questions and 85% of them are correct.
finally, this program is a way to activate your brain memory and leave it active.