一、知识梳理。1.分数加、减法的意义:分数加、减法的意义与整数加、减法的意义相同。2.同分母分数相加减:分母不变,只把分子相加减。3.异分母分数相加减:先通分,然后按照同分母分数加、减法的法则进行计算。最终结果能约分的要约成最简分数,是假分数的还可以化成带分数。4.分数加、减混合运算。(1)分数加、减混合运算与整数加减混合运算顺序相同。 First, knowledge combing. 1. Score plus, the meaning of subtraction: Score plus, the meaning of subtraction and integer plus, subtraction the same meaning. 2. Add and subtract with the denominator fraction: denominator unchanged, only add and subtract molecules. 3.Different denominators add and subtract: the first pass, and then follow the same denominator plus, subtract the law to calculate. The final result can be divided into the approximate minimum number of points, the fraction can be turned into fake points. 4. Score plus, minus mixing operation. (1) Addition, subtraction and subtraction Mixed operation and integer addition and subtraction mixed operation in the same order.