It means the method of decomposing an addend into two numbers, so that one part of the decomposed addend is added with another addend to get 10, and then the other part is added with 10. This is the way to add ten. Its basic principle is to make the sum of two numbers 10, and then convert it into the calculation method of addend.

When calculating addition and subtraction within 20, you need to master methods and skills. Learn mathematical calculation methods and skills such as adding ten, breaking ten and leveling ten with your children.