8.6×10.178.1-7.7÷0.7×5.2〔(8.1-5.6)×0.9-1〕×0.48.25×4.08+0.75×4.08+4.081.25×32×2.58.1
答案:2 悬赏:20 手机版
解决时间 2021-04-09 11:25
- 提问者网友:浮克旳回音
- 2021-04-09 07:19
8.6×10.178.1-7.7÷0.7×5.2〔(8.1-5.6)×0.9-1〕×0.48.25×4.08+0.75×4.08+4.081.25×32×2.58.1÷2+1.9÷2.
最佳答案
- 五星知识达人网友:舍身薄凉客
- 2021-04-09 08:08
解:①8.6×10.1,
=8.6×(10+0.1),
=8.6×10+8.6×0.1,
=86+0.86,
=86.86;
②78.1-7.7÷0.7×5.2,
=78.1-11×5.2,
=78.1-57.2,
=20.9;
③〔(8.1-5.6)×0.9-1〕×0.4,
=[2.5×0.9-1]×0.4,
=[2.25-1]×0.4,
=1.25×0.4,
=0.5;
④8.25×4.08+0.75×4.08+4.08,
=(8.25+0.75+1)×4.08,
=10×4.08,
=40.8;
⑤1.25×32×2.5,
=1.25×8×4×2.5,
=(1.25×8)×(4×2.5),
=10×10,
=100;
⑥8.1÷2+1.9÷2,
=8.1×0.5+1.9×0.5,
=(8.1+1.9)×0.5,
=10×0.5,
=5.解析分析:①、④、⑤、⑥可以直接或者变化后使用运算定律进行简算;
②、③按小数四则混算的顺序和计算法则直接计算.
点评:此题考查小数四则混合运算,细心计算,同时注意使用定律进行简算.
=8.6×(10+0.1),
=8.6×10+8.6×0.1,
=86+0.86,
=86.86;
②78.1-7.7÷0.7×5.2,
=78.1-11×5.2,
=78.1-57.2,
=20.9;
③〔(8.1-5.6)×0.9-1〕×0.4,
=[2.5×0.9-1]×0.4,
=[2.25-1]×0.4,
=1.25×0.4,
=0.5;
④8.25×4.08+0.75×4.08+4.08,
=(8.25+0.75+1)×4.08,
=10×4.08,
=40.8;
⑤1.25×32×2.5,
=1.25×8×4×2.5,
=(1.25×8)×(4×2.5),
=10×10,
=100;
⑥8.1÷2+1.9÷2,
=8.1×0.5+1.9×0.5,
=(8.1+1.9)×0.5,
=10×0.5,
=5.解析分析:①、④、⑤、⑥可以直接或者变化后使用运算定律进行简算;
②、③按小数四则混算的顺序和计算法则直接计算.
点评:此题考查小数四则混合运算,细心计算,同时注意使用定律进行简算.
全部回答
- 1楼网友:行雁书
- 2021-04-09 09:10
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