题目内容
(2012?泗县模拟)(怎样简便怎样算)
185-85÷5+83
1/8×2.75+0.125×1/4-12.5%
1.25×32×2.5
880×12.5.
185-85÷5+83
1/8×2.75+0.125×1/4-12.5%
1.25×32×2.5
880×12.5.
分析:(1)185-85÷5+83,根据整数四则混合运算的顺序按照整数四则运算的计算法则进行计算;
(2)
×2.75+0.125×
-12.5%,首先把分数和百分数化成小数,再运用乘法分配律进行简算;
(3)1.25×32×2.5,把32分解为:8×4,再运用乘法结合律进行简算;
(4)880×12.5,转化为:(800+80)×12.5,然后运用乘法分配律进行简算.
(2)
1 |
8 |
1 |
4 |
(3)1.25×32×2.5,把32分解为:8×4,再运用乘法结合律进行简算;
(4)880×12.5,转化为:(800+80)×12.5,然后运用乘法分配律进行简算.
解答:解:(1)185-85÷5+83,
=185-17+83,
=168+83,
=251;
(2)
×2.75+0.125×
-12.5%,
=0.125×2.75+0.125×0.25-0.125,
=0.125×(2.75+0.25-1),
=0.125×2,
=0.25;
(3)1.25×32×2.5,
=(1.25×8)×(4×2.5),
=10×10,
=100;
(4)880×12.5,
=800×12.5+80×12.5,
=10000+1000,
=11000.
=185-17+83,
=168+83,
=251;
(2)
1 |
8 |
1 |
4 |
=0.125×2.75+0.125×0.25-0.125,
=0.125×(2.75+0.25-1),
=0.125×2,
=0.25;
(3)1.25×32×2.5,
=(1.25×8)×(4×2.5),
=10×10,
=100;
(4)880×12.5,
=800×12.5+80×12.5,
=10000+1000,
=11000.
点评:此题考查的目的是掌握整数、小数、分数四则混合运算的顺序和它们的计算法则,并且能够灵活运用运算定律进行简便计算.
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