计算,能简便的用简便方法算.14.12+2.36+7.64+2.88??????(0.125×8-0.5)×4??????1000-450÷18×25
15×-5÷(+)×12?????????×〔÷(-)〕
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解:(1)14.12+2.36+7.64+2.88,
=(14.12+2.88)+(2.36+7.64),
=17+10,
=27;
(2)(0.125×8-0.5)×4,
=(1-0.5)×4,
=0.5×4,
=2;
(3)1000-450÷18×25,
=1000-25×25,
=1000-625,
=375;
(4)15×-5÷,
=15×-5×,
=(15-5)×,
=10×,
=;
(5)(+)×12,
=×12+×12,
=3+10,
=13;
(6)×[÷(-)],
=×[÷],
=××12,
=×12,
=4.
解析分析:(1)利用加法结合律简算;
(2)先算小括号里面的乘法,再算小括号里面的减法,最后算括号外的乘法;
(3)先算除法,再算乘法,最后算减法;
(4)、(5)运用乘法分配律简算;
(6)先算小括号里面的减法,然后把中括号里面的除法转化成乘法,再运用乘法结合律简算.
点评:运算定律是常用的简便运算的方法,要熟练掌握,灵活运用.