+ - mental exercises

Provides the following digit addition, subtraction, addition and subtraction mixed exercises:
· 2-digit and one digit
· 2-digit and two-digit
· 2-digit and two-digit and two-digit
· 3-digit and two-digit
· 3-digit and three-digit
· 4-digit and three-digit
· 4-digit and four-digit

To be able to see the daily progress in learning to facilitate recognition, but these statistics take the following diagram:
· Daily study time
· The number of daily exercise
· The average time an exercise
· Daily average score
· Daily contact records