用简便方法计算下面各题. (1)2.9×0.45+0.29×4.2+0.029×13 (2)3.84×9.6+0.96×61.6.
问题描述:
用简便方法计算下面各题.
(1)2.9×0.45+0.29×4.2+0.029×13
(2)3.84×9.6+0.96×61.6.
答
(1)2.9×0.45+0.29×4.2+0.029×13,=2.9×0.45+2.9×0.42+2.9×0.13,=2.9×(0.45+0.42+0.13),=2.9×1,=2.9;(2)3.84×9.6+0.96×61.6,=3.84×9.6+9.6×6.16,=(3.84+6.16)×9.6,=10×9.6,=96....