Significance and properties of the ratio of 1 and.

Meaning of (1) ratio: The division of two numbers is also called the ratio of two numbers.

(2) The nature of the ratio: the first and second terms of the ratio are multiplied or divided by the same number (except 0) at the same time, and the ratio remains unchanged, which is called the basic nature of the ratio.

(3) Find the ratio and simplify the ratio.

The method of finding the ratio: divide the previous item of the ratio by the latter item, and the result is that a number can be an integer, a decimal or a fraction. According to the basic properties of the ratio, the ratio can be reduced to the simplest integer ratio. Its result must be the simplest ratio, that is, the first term and the last term are prime numbers.

(4) Scale:

Distance on the map: actual distance = scale. Require to find the scale: know the distance and scale on the map and find the actual distance; Find the distance on the map by knowing the actual distance and scale. Line segment scale: The numbered line segment on the map indicates the actual distance corresponding to the ground.

2. The significance and nature of proportion

Significance of (1) ratio

Two expressions with equal ratios are called proportions. The four numbers that make up a proportion are called proportional terms. The two items at both ends are called external items, and the two items in the middle are called internal items.

(2) the nature of proportion

In proportion, the product of two outer terms is equal to the product of two inner terms. This is called the basic nature of proportion.

(3) Solution ratio: According to the basic properties of the ratio, if any three terms in the ratio are known, another unknown term of this number ratio can be found. Finding the unknown term in the proportion is called the solution ratio.

":"is a comparative symbol, pronounced "than". The number before the comparison symbol is called the first item of comparison, and the number after the comparison symbol is called the last item of comparison. The quotient obtained by dividing the former term by the latter term is called the ratio. Compared with division, the former term of ratio is equivalent to dividend, the latter term is equivalent to divisor, and the ratio is equivalent to quotient.

The ratio is usually expressed in fractions, decimals and sometimes integers. The last term of the ratio cannot be zero. According to the relationship between fraction and division, the former term of ratio is equivalent to numerator, the latter term is equivalent to denominator, and the ratio is equivalent to fractional value.