3.8X2.5X7.2 5.09X6.4+3.6X - 知识问答

3.8X2.5X7.2 5.09X6.4+3.6X5.09 12.8X10.1 简便算法是什么

1个回答

3.8X2.5X7.2
=[(4-0.2)X2.5]X7.2
=[10-0.5]X7.2
=72-3.6
=68.4
5.09X6.4+3.6X5.09
=5.09X(6.4+3.6)
=5.09X10
=50.9
12.8X10.1
=12.8X(10+0.1)
=128+1.28
=129.28
望采纳!

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