【题目】用简便方法计算。
①4×0.8×2.5×12.5
②0.65×14+87×0.65-0.65
③42÷[14-(50-39)]
④2.25×4.8+77.5×0.48
【答案】100,65,14,48
【解析】
解:①4×0.8×2.5×12.5
=(4×2.5)×(0.8×12.5)
=10×10
=100
②0.65×14+87×0.65-0.65
=0.65×14+87×0.65-0.65×1
=0.65×(14+87-1)
=0.65×100
=65
③42÷[14-(50-39)]
=42÷[14-11]
=42÷3
=14
④2.25×4.8+77.5×0.48
=2.25×4.8+7.75×4.8
=(2.25+7.75)×4.8
=10×4.8
=48