1. In the comparison formula, the number before the comparison symbol (:) is called the former item, the item after the comparison symbol is called the latter item, the comparison symbol is equivalent to the division symbol, and the quotient of the former item divided by the latter item is called the ratio.
For example, 3: 4: 5 is pronounced 3 to 4 to 5.
2. The ratio represents the relationship between two numbers, which can be expressed by a fraction, written in the form of a fraction, and read as several to several.
Example:12: 20 =12 ÷ 20 = = 0.612: 20.
Distinguish ratio and ratio: ratio is a number, usually expressed as a fraction, and can also be an integer or a decimal.
A ratio is a formula that represents the relationship between two numbers. It can be written as a ratio or a fraction.
3. The basic nature of the ratio: the first term and the second term of the ratio are multiplied or divided by the same number at the same time (except 0), and the ratio remains unchanged.
4. Simplified proportion: the simplified result is still a proportion, not a number.
(1), the two terms before and after the ratio are divided by the greatest common divisor at the same time.
(2) The simplified method of the ratio of two fractions is to multiply the last term in the previous paragraph by the least common multiple of the denominator, and then simplify the integer ratio. You can also find the ratio and write it out in the form of ratio.
(3), the ratio of two decimal places, move the position of the decimal point to the right, and also convert it into an integer ratio first.
5. Find the ratio: write the ratio symbol as a division symbol and then calculate it. The result is a number (or fraction), which is equivalent to quotient, not ratio.
6. The difference between ratio, division and fraction:
Division: Divider divisor symbol () Divider (not 0) Quotient invariant division is an operation.
Fraction: numerator fraction line (-) Denominator (cannot be 0) The basic property of a fraction is a number.
Ratio: the basic attribute ratio (not 0) of the item after the preceding comparison symbol (:) indicates the relationship between two numbers.
Quotient invariance: Divider and divisor are multiplied or divided by the same number (except 0) at the same time, and the quotient remains unchanged.
The basic nature of a fraction: the numerator and denominator are multiplied or divided by the same number at the same time (except 0), and the size of the fraction remains unchanged.