Kindergarten numbers 1 and 9, 4 and 6 are complementary, that is, they are all added to I0, and there are also 5 and 5, 3 and 7, 1 and 9, which is the method used by kindergartens to add to 10.

There is a formula in the "ten-point method": "19 19 is a good friend, 2828 is holding hands, 3737 is really intimate, and 4646 is walking together. Make a pair of hands in half. " Ten addition is the basic idea of carry addition. By using the method of "filling ten", carry addition can be transformed into the problem of adding several integers to 10, thus achieving the purpose of simplifying the complex. "

Ten-complement method is the basic method of carry addition within 20, which is based on the knowledge points of 10 plus a few that children have learned before. By using the method of filling ten, the carry addition within 20 can be transformed into the problem of adding several words to 10, which is familiar to children, and it embodies the transformation idea in mathematics, thus making it difficult and easy. It can not only improve the accuracy of calculation, but also effectively improve the speed of calculation, which is of great help to children's later learning.