0.25*0.8+0.2*0.25-0.25的简便算法我不知道

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0.25*0.8+0.2*0.25-0.25的简便算法我不知道

0.25*0.8+0.2*0.25-0.25的简便算法我不知道
0.25*0.8+0.2*0.25-0.25的简便算法
我不知道

0.25*0.8+0.2*0.25-0.25的简便算法我不知道
运用乘法分配律来计算 (0.25=0.25*1)
0.25*0.8+0.2*0.25-0.25
=0.25*(0.8+0.2-1)
=0.25*0
=0

0.25*0.8+0.2*0.25-0.25
=0.25*0.8+0.25*(0.2-1)
=0.25*0.8-0.25*0.8
=0

化为分数来算就会很快
1/4 * 4/5 + 1/5 * 1/4 - 1/4
=1/5 + 1/20 - 1/4
=(4+1-5)/20
=0

0.25*0.8+0.2*0.25-0.25
=0.25*(0.8+0.2-1)
=0.25*0
=0

其实这个式子0.25*0.8+0.2*0.25-0.25=0.25*0.8+0.2*0.25-0.25*1,对不对?所以接下来就用乘法分配律逆运算,把0.8,0.2,0.1提出来,变成0.25*0.8+0.2*0.25-0.25
=0.25*(0.8+0.2-1),运算,=0

乘法分配律逆运算
0.25*0.8+0.2*0.25-0.25
=0.25*(0.8+0.2-1)=0

0.25*0.8+0.2*0.25-0.25
=0.25×(0.8+0.2-1)
=0.25×0
=0

0.25*0.8+0.2*0.25-0.25
=0.25×(0.8+0.2-1)
=0.25×0
=0

原式=0.25*0.8+0.2*0.25-0.25
=0.25*(0.8+0.2-1)
=0