简便计算!1.2.5×9.8 2.1.25×25×3.2

问题描述:

简便计算!1.2.5×9.8 2.1.25×25×3.2
3.2.4-1.375+5分之3 4.3分之1÷7分之3×14分之5
1个回答 分类:数学 2014-11-13

问题解答:

我来补答
1.2.5×9.8
=2.5x(10-0.2)
=2.5x10-2.5x0.2
=25-0.5
=24.5
2.1.25×25×3.2
=(1.25x8)x(0.4x25)
=10x10
=100
3.2.4-1.375+5分之3
=2.4-+0.6-1.375
=3-1.375
=1.625
4 3分之1÷7分之3×14分之5
=1/3x7/3x5/14
=5/18
 
 
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