1, carry addition 9+2=? The combination of the two is 1, and together with 9 is 10, which stands for 10. Add the remaining 1 and it is 1 1. A preliminary understanding of the principle of "full ten goes forward one bit and enters one" is the basis for learning the addition vertical form in the future.

2, abdication subtraction. 12-9=? Bundle the sticks into a bundle 10, and put two sticks respectively. 10 Remove 9, leaving 1, and then combine with 2, which is 3. I have initially understood a truth, that is, if the reduction is not enough, it will be ten.

Second, it is difficult for children to learn carry addition and abdication subtraction within 20 years from preschool to senior one. Children can easily accept addition and subtraction within 10, and the fingers are exactly ten, so snapping fingers is very direct and simple.

Carry and abdication are somewhat abstract, so you can't take off your socks. At this time, it should still add up to 10, such as 7+8=? Break 7 into 2+5, round 2 and 8, and then add 5. Subtraction also begins with the decomposition of 10, such as 15-8=? First use 10-8=2, and then use 2+5=7. The premise of carrying abdication is that children within 10 can master it.

Extended data:

Carry addition, one of mathematical operations, one of addition. For example, in decimal system, if the number of digits on one digit adds up to ten, then write the number of digits added up on this digit and input the number on the tenth digit to the next digit.

A mathematical operation, an addition. When two numbers are added, every time the result of a certain bit is greater than or equal to 10, you need to count 1 to the next bit, which is the carry. For example:

48

+ 56

————

= 104

8+6 = 14 & gt； 10 rises by one place (ten places) to 1.

4+5 plus rounded 1, that is, 4+5+ 1= 10 also needs to be rounded up by one bit (ten bits) to 1.

When there is carry addition in the operation, it is called "carry addition".

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