(a), the calculation rules of fractional multiplication:

1, Fraction multiplied by integer: the product of numerator multiplied by integer is numerator, and the denominator remains unchanged. (Integer and denominator divisor)

2. Fraction and fractional multiplication: use the product of molecular multiplication as the numerator and the product of denominator multiplication as the denominator.

3. In order to simplify the calculation, the points that can be reduced are reduced first and then calculated.

Note: When multiplying with a fraction, the fraction should be converted into a false fraction before calculation.

Figure 1

decimal

The significance of fractional division:

Fractional division has the same meaning as integer division, which refers to the operation of knowing the product of two factors and one of them and finding the other factor.

The calculation rule of fractional division: dividing by a number that is not 0 is equal to multiplying the reciprocal of this number.

Law (when the fractional division is large): (1), when the divisor is greater than 1, the quotient is less than the dividend;

Figure ii

(2) When the divisor is less than 1 (not equal to 0), the quotient is greater than the dividend; (3) When the divisor is equal to 1, the quotient is equal to the dividend.

This is called parenthesis. In an equation, if there are both parentheses, you should count the parentheses first and then the parentheses.