题目内容
【题目】递等式计算,能简便运算的要简便运算。
47.5÷(2.5×0.475)
0.25×0.32×1.25
(8.25﹣7)÷(2.7﹣2.66)
15.5﹣15.5×1.5÷15.5×1.5
6.25×7.4+0.26×62.5﹣6
【答案】40;0.1;21.875;13.25;56.25
【解析】
(1)根据a÷(b×c)=a÷b÷c进行简便计算;
(2)把0.32化为0.4×0.8,根据乘法交换律和乘法结合律进行简算;
(3)先算小括号里的减法,再算小括号外的除法;
(4)观察算式后,可以先算15.5÷15.5,再进行计算会更简便;
(5)将6化为小数6.25,0.26×62.5根据乘法性质变为2.6×6.25,再应用乘法分配律进行简算。
(1)47.5÷(2.5×0.475)
=47.5÷0.475÷2.5
=100÷2.5
=40
(2)0.25×0.32×1.25
=0.25×0.4×0.8×1.25
=(0.25×0.4)×(0.8×1.25)
=0.1×1
=0.1
(3)(8.25﹣7)÷(2.7﹣2.66)
=0.875÷0.04
=21.875
(4)15.5﹣15.5×1.5÷15.5×1.5
=15.5﹣15.5÷15.5×1.5×1.5
=15.5﹣15.5÷15.5×(1.5×1.5)
=15.5﹣1×2.25
=15.5﹣2.25
=13.25
(5)6.25×7.4+0.26×62.5﹣6
=6.25×7.4+2.6×6.25﹣6
=6.25×(7.4+2.6﹣1)
=6.25×9
=56.25
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