14× = | ×5= | × = | 12× = | 3× = |
7× = | 4.8+0.82= | 3 -2.7= | ( +2)×9= | ( - )×2= |
解:14× = , | ×5= , | × = , | 12× =8, | 3× = , |
7× = , | 4.8+0.82=5.62, | 3 -2.7=1.1, | ( +2)×9=21, | ( - )×2= . |
分析:分数乘法:分子相乘的积做分子,分母相乘的积做分母.
(
+2)×9,(
-
)×2运用乘法分配律简算.点评:本题主要考查了分数乘法的计算方法,计算时要细心,把结果化成最简分数.
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