【题目】计算下面各题,能简便计算的用简便方法计算。
18×9.9 0.25×32×12.5 ×37-2÷ ×[÷(-)]
【答案】16.2;100;25;4
【解析】
18×9.9,把9.9写成10-0.1,用乘法分配律简算;
0.25×32×12.5,把32写成4×8,用乘法结合律简算;
×37-2÷,用乘法分配律简算;
×[÷(-)],根据四则混合运算顺序计算。
18×9.9
=18×(10-0.1)
=18×10-18×0.1
=18-1.8
=16.2
0.25×32×12.5
=0.25×(4×8)×12.5
=(0.25×4)×(8×12.5)
=1×100
=100
×37-2÷
=×37-2×
=×(37-2)
=×35
=25
×[÷(-)]
=×[÷]
=××12
=4



