Summary of calculation method of fractional multiplication and division 1. Fractional multiplication: 1. Calculation method of fractional multiplication by integer: fractional multiplication by integer, the product of fractional numerator multiplied by integer is numerator, and the denominator remains unchanged. 2. Fraction (integer) multiplied by fraction, that is, the calculation method of a number multiplied by fraction: fraction multiplied by fraction, numerator product as new molecule, denominator product as new denominator. If you can cut, cut first, then calculate. The result is to try the simplest score. In the process of reduction, it must be the reduction of numerator denominator and integer denominator. If there is a score, you should turn it into a fake score and calculate it according to the calculation method. 3. In several groups of multiplication formulas with equal products, the bigger one factor is, the smaller the other factor is (big to small, small to big). 4. Reciprocal: Two numbers whose product is "1" are reciprocal to each other. The reciprocal of "1" is "1", and "0" has no reciprocal. 5. How to find the reciprocal of a number: divide by "1". The reciprocal of true fraction (false fraction), directly exchange the position of numerator and denominator; To find the reciprocal of the band fraction, we must first turn the band fraction into a false fraction, and then exchange the positions of the numerator and denominator; To find the reciprocal of the decimal, we must first divide the decimal into numbers, and then exchange the positions of the numerator and denominator; Find the reciprocal of an integer, write the integer as denominator, and the numerator is "1". 2. Fractional division 1: It has the same meaning as integer division. It is an operation to find the other factor by knowing the product of two factors and one of them.