Importance of (1) fractional multiplication:

1, the fractional multiplication of integers has the same meaning as integer multiplication, and it is a simple operation to find the sum of several identical addends.

"Fraction multiplied by integer" means that the second factor must be an integer, not a fraction.

2. Multiplying a number by a fraction means finding the fraction of a number.

"A number multiplied by a fraction" means that the second factor must be a fraction, not an integer. The first factor is anything. )

(2) Calculation rules of fractional multiplication:

1, the arithmetic of decimal times integer is: numerator times integer, denominator remains unchanged.

(1) In order to make the calculation simple, it can be reduced first and then calculated. (integer denominator reduction) (2) reduction is to reduce the common factor with the following integer and denominator. (Integer cannot be multiplied by denominator, and the calculation result must be the simplest fraction).

2. The arithmetic of fractional multiplication is: use the product of molecular multiplication as numerator and the product of denominator multiplication as denominator. (numerator times numerator, denominator times denominator)

(1) If the fractional multiplication formula contains a band fraction, the band fraction should be converted into a false fraction before calculation.

(2) The method of fractional simplification is that the numerator and denominator are divided by their common factors at the same time.

(3) In the process of multiplication, the divisor is to cross out two divisible numbers in the numerator and denominator, and then write the divisor above and below respectively. (After reduction, the numerator and denominator can no longer contain common factors, so the calculated result is the simplest score).

(4) The basic nature of the fraction: the numerator and denominator are multiplied or divided by the same number (except 0) at the same time, and the size of the fraction remains unchanged.