Ten-break method: Ten-break method, also called "borrowing ten method", is a calculation method used in the subtraction of abdication within 20. By using the method of breaking ten, the abdication subtraction within 20 can be transformed into the addition and subtraction within 10 that students are familiar with, thus making simplification difficult.

Example: As shown in the figure.

When calculating 13 minus 7, considering that unit 3 minus 7 is not enough, we borrow 10 from ten digits to subtract it, and subtract 7 from 10 to get 3, and then add 3 to unit 3 to equal 6. This is a ten-way break.

9+8=9+ 1+7= 17

14-9= 10-9+4=5

13-4= 10-4+3=6+3=9

18-9= 10-9+8= 1+8=9

1 1-5= 10-5+ 1=5+ 1=6

9+6= 10+5= 15

8+6= 10+4= 14

7+4= 10+3= 13

Extended data:

The formula of breaking the law of ten: look at a large number, divide it by 10, then subtract it, and add the remainder.

Ten MINUS nine, a few plus one. Ten MINUS seven, a few plus three. Ten MINUS five, a few plus five. A dozen MINUS three, a few plus seven. Ten MINUS eight, a few plus two. Ten MINUS six, a few plus four. Ten MINUS four, a few plus six. A dozen MINUS two, a few plus eight.

"Breaking the Ten Laws" means opposing the Ten Laws. Just let the children know that a dozen can be divided into 10 and a few, and a few+a few equals a few.