计算(能简算的要简算)????
99×8.4+0.84???????????????????
(37.62+20.76)÷0.042
4.8×6.2÷12.4????????
3.75÷[0.03×(1.34-0.84)].
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解:(1)99×8.4+0.84
=990×0.84+0.84×1,
=(990+1)×0.84,
=991×0.84,
=832.44;
(2)(37.62+20.76)÷0.042
=58.38÷0.042,
=843÷0.6,
=1390;
(3)4.8×6.2÷12.4
=29.76÷12.4,
=2.4;
????????
(4)3.75÷[0.03×(1.34-0.84)]
=3.75÷[0.03×0.5],
=3.75÷0.015,
=250.
解析分析:(1)依据积不变的规律,将算式中的99扩大10倍,8.4缩小10倍,将0.84改写成0.84×1,然后再利用乘法分配律进行计算即可;
(2)、(3)、(4)按照小数的四则混合运算进行计算即可得到