简便计算
12.8-0.5×0.5-0.75????????????
1.25×3.2×0.8????????????
8.37×1.4+8.6×8.37.
网友回答
解:(1)12.8-0.5×0.5-0.75,
=12.8-0.25-0.75,
=12.8-(0.25+0.75),
=12.8-1,
=11.8;
(2)1.25×3.2×0.8,
=1.25×0.8×3.2,
=1×3.2,
=3.2;
(3)8.37×1.4+8.6×8.37,
=8.37×(1.4+8.6),
=8.37×10,
=83.7.
解析分析:(1)先求出0.5×0.5=0.25,运用减法的性质简算;(2)运用乘法交换律与结合律简算;(3)运用乘法分配律的逆运算简算.
点评:此题考查了小数四则混合运算的简算,在做题时要注意分析式中数据,运用所学定律或运算性质简算.