题目内容
计算下面各题,能用简便算法的用简便算法 3.045+2.7×6.9= |
18.94-2.5×4= |
3.65×2.8+3.65×7.2= | 13.54×102-2×13.54= |
分析:(1)先算乘法,再算加法;
(2)先算乘法,再算减法;
(3)(4)运用乘法分配律简算.
(2)先算乘法,再算减法;
(3)(4)运用乘法分配律简算.
解答:解:(1)3.045+2.7×6.9,
=3.045+18.63,
=21.675;
(2)18.94-2.5×4,
=18.94-10,
=8.94;
(3)3.65×2.8+3.65×7.2,
=3.65×(2.8+7.2),
=3.65×10,
=36.5;
(4)13.54×102-2×13.54,
=13.54×(102-2),
=13.45×100,
=1345.
=3.045+18.63,
=21.675;
(2)18.94-2.5×4,
=18.94-10,
=8.94;
(3)3.65×2.8+3.65×7.2,
=3.65×(2.8+7.2),
=3.65×10,
=36.5;
(4)13.54×102-2×13.54,
=13.54×(102-2),
=13.45×100,
=1345.
点评:本题考查了四则混合运算,注意运算顺序和运算法则,灵活运用所学的运算定律进行简便计算.
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