When calculating, the decimal points are 10 and single digits, and 10 is subtracted from the subtraction, and the difference is added with single digits. For example:
15-7= 10-7+5=3+5=8
16-8= 10-8+6=2+6=8
12-7= 10-7+2=3+2=5
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Subtraction by abdication, a special mathematical term, can also be called subtraction by borrowing. That is, when two numbers are subtracted and the number of digits to be subtracted is not enough, borrowing the previous digit is equivalent to adding 10 to this digit, and then calculating.
Calculated on the draft paper: 5+05 of 65438 minus 4 of 24, the result is 1, and then subtracted by 10 to get 9, which is a unit, while 2 of the decimal digits is borrowed, and the calculation of the decimal digits becomes 1- 1, which is 0 and the result is 9. If ten people want to continue to abdicate, repeat. Of course, this can't be written in a formal place.
Abdication subtraction Baidu Encyclopedia