The method of "breaking ten" is to divide a dozen by 10 and a few, then subtract the subtraction from 10, and then add the subtraction result to the few. "Breaking the Ten Laws" means opposing the Ten Laws. The key point is to let children understand that more than ten can be divided into 10 and several.

Ten formula: minus nine plus one, minus eight plus two, minus seven plus three, minus six plus four, minus five plus five, minus four plus six, minus three plus seven, minus two plus eight, minus one plus nine. There is also a formula: a dozen MINUS nine, a few plus one; Ten MINUS seven, a few plus three; A dozen MINUS five, a few plus five; One dozen MINUS three, several plus seven; A dozen MINUS eight, a few plus two; A dozen MINUS six, a few plus four; A dozen MINUS four, a few plus six; A dozen MINUS two, a few plus eight.

Decimal method is a mathematical calculation method, that is, when the number of digits is not reduced enough, subtract 10 by subtraction and add the remainder to the number of digits, that is, decimal method. For example: 1 1-4, 1-4 digits are not enough for reduction, so subtract 4 from11(10+1),10.

Among them, "adding ten" method and "breaking ten" method are mutually transformed, and adding ten method is the basic idea of carry addition within 20. By using the method of filling ten, the carry addition within 20 can be transformed into the familiar problem of 10 plus several, which makes it difficult and easy.

For example, 9+5, divide 5 into 1 and 4, because 9 adds up to 10 and lacks 1, so it is divided into 1. So 9+5 is divided into 9+ 1= 10, then 10+4= 14, and finally 9+5= 14.