题目内容
5.脱式计算.(能简算的要简算)(1)49×0.25×8;
(2)7.3×0.64+9.36;
(3)1.01×0.99;
(4)0.85×7.5+8.5×0.25.
分析 (1)运用乘法的结合律进行简算;
(2)先算乘法,再算加法;
(3)把0.99化成1-0.01,再运用乘法的分配律进行简算;
(4)运用乘法的分配律进行简算.
解答 解:(1)49×0.25×8
=49×(0.25×8)
=49×2
=98;
(2)7.3×0.64+9.36
=4.672+9.36
=14.032;
(3)1.01×0.99
=1.01×(1-0.01)
=1.01×1-1.01×0.01
=1.01-0.0101
=0.9999;
(4)0.85×7.5+8.5×0.25
=0.85×7.5+0.85×2.5
=0.85×(7.5+2.5)
=0.85×10
=8.5.
点评 完成本题要注意分析式中数据,运用合适的简便方法计算.
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