1, decimal method: it is a calculation method, that is, if the unit is not reduced enough, subtract the subtraction with 10 and add the remainder with the number in the unit, that is, decimal method.

For example, if we calculate 13-5, the first step is to divide 13 into 10 and 3. We know that 10-5 equals 5, and then 5 plus 3 finally equals 8. So13-5 =10+3-5 =10-5+3 = 5+3 = 8.

2. The method of ten times ten is the process of decomposing the smaller addend of two addends into the sum of two numbers, so that the sum of one part and the other addend is 10.

Calculate by the method of ten: 9+3, divide 3 by 1 and 2. Because 9 is ten and lacks 1, it is divided into 1. So 9+3, the decomposition calculation is 9+ 1 = 10, and finally 10+2 = 12.

Extended data:

First, let the children remember the formula of "Ten-fill Method"

The method of adding up to ten may be difficult at first glance, but it seems difficult to get started. In fact, the method of adding up to ten has a special formula. If you remember the formula and then do the problem, the difficulty will be greatly reduced.

Formula: 9 to 1, 8 to 2, 7 to 3, 6 to 4, 5 to 5, that is, 9 plus 1 equals 10, 8 plus 2 equals 10, and so on! At the beginning, it may be difficult for children to remember, so children need to practice deliberately here, that is, before doing the problem, parents guide their children to recite the formula first, and then do the problem.

Second, split the smaller number in the formula with the previous number to make up 10.

According to the formula of ten addition, we can know that 9 needs 1, that is, 4 divided by 3 and 1, 1 and 9 make up 10. Take that problem as an example, say, 7 plus 4. In this formula, we first split the smaller number 4 into 3 and 1, and 3 can add up with the previous 7 to be 10.