10 times 10 method is often used for addition within 20.

For example: 9+6 =?

You can divide 6 into "1" and "5", use 9+ 1 = 10, then use 10 and add the remaining 5, that is, 10+5 = 15.

9 can be divided into "5" and "4", 4+6 = 10, and then 10.

Add the remaining 5, that is, 10+5 = 15.

You can also split 9 into "4" and "5", or 6 into "5" and "1", where 5+5 = 10, and the remaining 4+ 1 = 5, and then use 10.

Add 5, that is, 10+5 = 15.

Second, break the ten laws.

Subtract several from a dozen. When the number of units is not enough, subtract the subtraction with 10 and add the remainder to the number of units, that is, break the ten method.

For example: Calculate 13-8 =?

We subtract 8 from 10, leaving 2, and then add a number with this 2.

3, you can get 5.

Namely: 10-8 = 2, 3+2 = 5.

Extended data

Ten-level method

15-8, unit 5 is not enough to subtract 8, so first subtract unit 5, it becomes an integer 10, and then subtract 3 from 10 (because 8 = 5+3), and the answer is 10-3 = 7.

Compared with the method of leveling ten, the method of breaking ten is more common, so it is good to master it skillfully.