正确、合理、灵活的计算下面各题. (+-)×1.20.25×32×1.25×7.5+(1-)÷2×1.25+1×2.4-125%×(-)÷.
网友回答
解:(1)(+-)×1.2,
=×1.2+×1.2-×1.2,
=0.6+0.4-1,
=1-1,
=0;
(2)0.25×32×1.25,
=(0.25×4)×(8×1.25),
=1×10,
=10;
(3)×7.5+(1-)÷,
=×7.5+÷,
=(7.5+)×,
=10×,
=2;
(4)2×1.25+1×2.4-125%,
=(22.4-1)×1,
=4×1,
=5;
(5)×(-)÷,
=,
=,
=1.
解析分析:(1)(3)(4)运用乘法分配律解答,(2)化32=4×8,再运用乘法交换律和结合律解答,(5)按照先算括号里面的,再从左到右顺序计算顺序解答.
点评:本题主要考查学生依据四则运算计算顺序进行计算,以及运用简便算法解决问题的能力.