用简便方法计算.1.8×0.36+0.18×4.2+22×0.0180.36×7.4+0.72×1.3.

发布时间:2020-08-09 04:20:04

用简便方法计算.
1.8×0.36+0.18×4.2+22×0.018
0.36×7.4+0.72×1.3.

网友回答

解:(1)1.8×0.36+0.18×4.2+22×0.018,
=1.8×0.36+1.8×0.42+0.22×1.8,
=1.8×(0.36+0.42+0.22),
=1.8×1,
=1.8;

(2)0.36×7.4+0.72×1.3,
=0.36×7.4+0.36×2×1.3,
=0.36×(7.4+2×1.3),
=0.36×(7.4+2.6),
=0.36×10,
=3.6.
解析分析:(1)根据数字特点,原式变为1.8×0.36+1.8×0.42+0.22×1.8,运用乘法分配律简算;
(2)原式变为0.36×7.4+0.36×2×1.3,运用乘法分配律简算.

点评:简算时看到此类“几个乘法相加减”的题,先观察这几个乘法有没有相同因数,或者能不能转化出相同因数.
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