Question

54.9*0.38和4.05+37.85用简便方法

Answer 1

54.9x0.38=（55-0.1）×0.38=55×0.38-0.1×0.38=（50+5）×0.38-0.1×0.38=50x0.38+5x0.38-0.1x0.38=19+1.9-0.038=20.9-0.038=20.8624.05+37.85=41.9