The easiest way to quickly learn how to count

To learn all the options for addition and subtraction within 20 not a child. But this knowledge is required to successfully master more complex techniques of computing. To help solve the problem of the book-machine. Her child quickly and easily memorize boring tables with examples, will learn the basic techniques of oral computation, and learn to test yourself. And all this without the tedious cramming in the process a funny game with magic disc! Simple and effective: turn the disc, solved examples, check my answers, remember. Table cases of addition and subtraction within 20 are distributed on three circles. And the fourth round is a bonus! Here are examples for improving the skills of oral computation. Learning by playing!