+ = | 1÷ = | ×12× = | × + × = | + + + = |
8- = | 2.25-0.25= | × ÷ = | ÷ - × = | 5- - = |
解: + =![]() | 1÷ =![]() | ×12× =3 | × + × =14 | + + + =2 |
8- =7![]() | 2.25-0.25=2 | × ÷ =![]() | ÷ - × =![]() | 5- - =4 |
分析:此题分为三个类型:(1)分数的加法减法,先通分,化为同分母的分数,分母不变,分子相加、减;(2)分数的乘法,分子和分子相乘做分子,分母和分母相乘做分母,能够约分的要先约分;(3)分数除法,除以一个数对应乘这个数的倒数.
点评:本题主要考查了分数的加法和减法的计算方法及分数乘法和除法的计算方法,注意能够简算的要简算.
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