Add and Subtract Mental Math

接受挑战，成为加法和减法运算冠军

Mental Math Challenge: Add and Subtract app is the most challenging app for mastering addition and subtraction problems. This app is useful for all ages. Take the challenge and become a champion in addition and subtraction operations. Whoever become a champion in this challenge will be able to add and subtract with lightening speed.

Mental Math Challenge: Add and Subtract Features:

-Step by step instructions for easy mental addition and subtraction.

-Separate lessons for 2 digit, 3 digit and 4 digit number operations.

-Very interesting and easy to remember math tricks.

-Challenging tests that have levels and achievements for motivation.

-Each test has 3 levels with increasing difficulty.

-Will be very useful for kids going for oral math quizzes

-Will increase number sense in kids