计算下面各题,能简便计算的用简便方法计算.
4.82-5.2÷0.8×0.6
[-(-)]÷×+×12.3×9957.5-14.25-153.2×12.5×0.25.
网友回答
解:(1)4.82-5.2÷0.8×0.6,
=4.82-6.5×0.6,
=4.82-3.9,
=0.92;
(2)[-(-)]÷,
=[-]÷,
=÷,
=;
(3)×+×,
=(+)×,
=1×,
=;
(4)12.3×99,
=12.3×(100-1),
=12.3×100-12.3×1,
=1230-12.3,
=1217.7;
(5)57.5-14.25-15,
=57.5-(14.25+15),
=57.5-30,
=27.5;
(6)3.2×12.5×0.25,
=8×0.4×12.5×0.25,
=(8×12.5)×(0.4×0.25),
=100×0.1,
=10.
解析分析:(1)先算除法,再算乘法,最后算减法;
(2)先算小括号里面的减法,再算中括号里面的减法,最后算括号外的除法;
(3)运用乘法分配律简算;
(4)先把99分解成100-1,再运用乘法分配律简算;
(5)根据减法的性质简算;
(6)先把3.2分解成0.4×8,再运用乘法交换律、结合律简算.
点评:本题考查了四则混合运算,注意运算顺序和运算法则,灵活运用所学的运算定律进行简便计算.