12.5×198÷(18÷8)
1.2×8.64+1.136×12-2×0.12×50.
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解:(1)12.5×198÷(18÷8),
=12.5×198÷2.25,
=12.5×(8×24.75)÷2.25,
=(12.5×8)×24.75÷2.25,
=100×24.75÷2.25,
=2475÷2.25,
=1100;
(2)1.2×8.64+1.136×12-2×0.12×50,
=1.2×8.64+11.36×1.2-(2×50)×0.12,
=1.2×8.64+11.36×1.2-10×1.2,
=1.2×(8.64+11.36-10),
=1.2×(20-10),
=1.2×10,
=12.
解析分析:(1)先算出小括号里面的除法,然后把198分解成8×24.75,再运用乘法结合律简算;
(2)先变形,把每部分的加数中都变成含有1.2这个因数,然后再运用乘法分配律简算.
点评:本题是较复杂的简便运算;运算定律是常用的简便运算的方法,要熟练掌握,灵活运用.