Who knows how to supplement and supplement abacus mental arithmetic?

Complement: If the sum of two numbers is 5, the two numbers are said to be complementary. The complement of 1 is 4, the complement of 2 belongs to 3, the complement of 3 is 2, and the complement of 4 is 1.

Complement: If the sum of two numbers is 10, the two numbers are said to be complementary. The complement of 1 is 9, that of 2 is 8, that of 3 is 7, that of 4 is 6, that of 5 is 5, that of 6 is 4, that of 7 is 3, that of 8 is 2 and that of 9 is 1.

The formula is as follows:

1, the bead is not enough, and the next 5 is reduced;

2, the beads are not reduced enough, go to 5' s complement;

3, a file is not enough, plus 10 minus make up;

4. If the number of files is not enough, subtract 10 and add the complement to make up the number: the two numbers add up to 5; Complement: The sum of two numbers is equal to 10.

Extended data:

A negative number can be replaced by its positive complement, which can be obtained by adding the negative number itself to the module.

When a positive number and a negative number are mutually remainder, the sum of the absolute values of these two numbers is a module, and the complement of the positive number is itself.

The biggest application point of complement is that when dealing with addition and subtraction, different calculation methods will not be used because of positive numbers and negative numbers. As long as there is an addition circuit, it can handle the addition of various signed numbers, and the subtraction can be expressed by adding the complement of one number to another, so as long as there is an addition circuit and a complement circuit, it can complete the addition and subtraction of various signed numbers, and the circuit design is quite convenient.

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