A÷b is called a∶b, which means that the ratio belongs to another form of "division" and mainly represents the relationship between two numbers.

In A: B, A is called the former term of the ratio, and B is called the latter term of the ratio (the latter term of the ratio cannot be 0).

The quotient obtained by dividing the former term of the ratio by the latter term of the ratio is called the ratio.

Ratio can refer to the division of two similar quantities or different quantities (that is, the division relationship between two numbers can also be called ratio. ).

Mainly used for: finding the number of copies in the relationship between the total number and the number of copies; Looking for multiplicity in multiple relationships.

Second, the method of finding the ratio

The former term of the ratio and the latter term of the ratio = ratio;

The former term of the ratio = the latter term of the ratio × the ratio; ?

The latter term of the ratio = the former term of the ratio.

The first and last items of the ratio are multiplied or divided by the same number (except zero), and the ratio remains unchanged.

Third, the result of the ratio should be the simplest ratio, that is, the first term and the last term of the ratio are the simplest integer ratios of prime numbers.

Simplified method of ratio:

(1) integer ratio: divide the front and back terms of the ratio by their greatest common divisor (or common divisor) until it becomes the simplest ratio.

② Decimal ratio: First rewrite the decimal ratio into an integer ratio, and then simplify it by simplifying the integer ratio.

③ Fractional ratio: First rewrite the fractional ratio into an integer ratio, and then simplify it by simplifying the integer ratio.