First, the significance of fractional multiplication
The significance of fractional multiplication is the same as that of integer multiplication, and finding the sum of several identical addends is a simple operation.
The calculation method of fractional multiplication: numerator times numerator, denominator times denominator, and what can be reduced is reduced first.
Second, the calculation rules of fractional multiplication
Fraction multiplied by integer, numerator is the product of fractional and integer multiplication, denominator remains unchanged.
Fractions are multiplied by fractions, the product of numerator multiplication is numerator, and the product of denominator multiplication is denominator.
When a fraction is multiplied by a decimal, the number of components of the fraction can be recalculated, or the fraction can be converted into a decimal and then calculated.
Third, the application of fractional multiplication
Given the quantity of unit 1, find a fraction of it and calculate it by multiplication.
Given a quantity, find its reciprocal and divide it by 1.
Fourthly, the ratio problem in fractional multiplication
If the ratio of two quantities is certain, then the two quantities are in direct proportion.
If the ratio of two quantities is uncertain, then the two quantities are not proportional.
Verb (abbreviation of verb) matters needing attention
In fractional multiplication, if the numerator and denominator of a fraction have a common factor, then the fraction should be reduced before calculation.
In fractional multiplication, if there is no common factor between the numerator and denominator of a fraction, the numerator or denominator can be divided first and then divided.
Pay attention to unit conversion and carry in fractional multiplication.
In fractional multiplication, we should pay attention to the sign problem. If two numbers are multiplied, the negative signs should be added together.
In fractional multiplication, we should pay attention to simplification. If we encounter a score, we must first turn it into a pseudo-score, and then calculate it.
Pay attention to the test questions in fractional multiplication and check whether the calculation results are correct.
Calculation method of fractional multiplication
1. Multiply two molecular fractions to get a new molecular fraction.
2. Multiply the denominators of the two fractions to get the denominator of the new fraction.
3. Simplify the new fraction so that its numerator and denominator are prime numbers.