The method is as follows: 1. Make friends training lets students know which two numbers add up to 10, that is, let students know that 9' s friends are 1, 8' s friends are 2, 7' s friends are 3, 6' s friends are 4 and 5' s friends are 5.

2. Computational training with addend less than 5 and equal to 5.

Example: 9+5 or 5+9, use your fingers to represent the smaller number, and memorize the larger number as 10, that is, use your fingers to represent 5 and stick out 5 fingers. Because 9' s friend is 1, the extended five fingers subtract one finger, leaving four. Add up 10 and 4 in your head, so 9. 9+4 or 4+9, 9+3 or 3+9; 9+2 or 2+9 can use this method. This method can be summarized as follows:

9 plus MINUS 1 from the extended finger, 8 plus MINUS 2 from the extended finger, 7 plus MINUS 3 from the extended finger ... The remaining fingers are more than ten.

3. Computational training with both addends exceeding 5.

1. If both addends exceed 5, choose the smaller one to subtract 5. For example, the smaller number is 6 minus 5, leaving 1, 7 minus 5, leaving 2, 8 minus 5, leaving 3, and if they are all 9, 9 minus 5, leaving 4. The number left in the finger, memory 15.

2. For example, 9+6 or 6+9, and the smaller number is 6. Subtract 5 from 6 to get 1, point to the remainder of 1 with your finger, and subtract 1 to get 0. What you remember in your mind is 15, 15 plus 0 to get 15, that is. Remember 15 in your mind, because 9' s friend is 1. Subtract 1 from the finger's 2, leaving 1, 1 plus 15 to get 16, that is, 9+7= 16.

9+8 or 8+9 subtracts 5 from 8 to get 3, then subtracts 1 to get 2, and mentally adds 15 and 2 to get 17, that is, 9+8= 17. And so on, you can complete 8+7 or 7+8, 6+8 or 8+.