수학쟁이(math game)

* Arithmetic operations are the basic tools underlying mathematics.

* With repeated practice, you gain confidence in math.

* Anyone can practice arithmetic operations easily and conveniently.

* Mental arithmetic is an effective way to acquire computational power.

* Mental arithmetic trains the brain and builds confidence in math.

* You can see the scoring results and intermediate results.

* Weak arithmetic operations are overcome by being able to solve the wrong problem again.

* It is easy to check because you can see the history of solving the arithmetic operation.