54.9x0.38简算?9.8x25简算?4.05+37.85简算?

分类: 作业答案 • 2022-01-24 12:22:30

问题描述：

答

54.9×0.38
=(55-0.1)×0.38
=55×0.38-0.038
=11×1.9-0.038
=20.9-0.038
=20.862
9.8×25
=(10-0.2)×25
=250-5
=245
4.05+37.85=41.9