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一、盘点知识。(一)分数乘法。1.分数乘法的意义。分数乘法的意义与整数乘法的意义相同,都是表示“求几个相同加数和的简便运算”。2.分数乘法的计算法则。(1)分数乘整数:用分数的分子与整数相乘的积作分子,分母不变;(2)分数乘分数:用分子相乘的积作分子,分母相乘的积作分母。3.解决问题。“求一个数的几分之几是多少”的应用题,用乘法计算。解题方法是用这个数乘几分之几。基本数量关系式是:单位“1”的量×分率=分率所对应的量。(二)分数除法。1.倒数的意义。乘积是1的两个数互为倒数。求一个数的倒数的方
First, inventory knowledge. (A) fractional multiplication. 1. The meaning of fractional multiplication The meaning of the fractional multiplication is the same as the meaning of the integer multiplication, both of which are simple functions for expressing the same sum of sums. 2. The law of fractional multiplication. (1) Fraction multiplied by an integer: The product of fractional numerator and integer multiplication multiplies the numerator and denominator; (2) Fractional fractional fraction: The product of multiplication by numerator and numerator, and the product of the denominator multiplication as the denominator. Solve the problem “Seeking a few how many is the number of ” application questions, calculated by multiplication. The solution is to multiply this number by a few. The basic quantitative relationship is: unit “1 ” amount x fraction = fraction corresponding to the amount. (B) fractional division. The meaning of countdown The product of 1 is the reciprocal of the two numbers. Find a countdown to the square