题目内容
【题目】用简算方法计算下面各题.
(1)12.5×(0.7×0.8)
(2)4.2×8+8×5.8
(3)8×(25﹣1.25)
【答案】(1)12.5×(0.7×0.8)
=(12.5×0.8)×0.7
=10×0.7
=7
(2)4.2×8+8×5.8
=(4.2+5.8)×8
=10×8
=80
(3)8×(25﹣1.25)
=8×25﹣1.25×8
=200﹣10
=190
【解析】解:(1)12.5×(0.7×0.8)
=(12.5×0.8)×0.7
=10×0.7
=7
(2)4.2×8+8×5.8
=(4.2+5.8)×8
=10×8
=80
(3)8×(25﹣1.25)
=8×25﹣1.25×8
=200﹣10
=190
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