12.59.8-4.95怎么简便

分类: 作业答案 • 2022-01-07 11:51:28

问题描述：

12.5*9.8-4.9*5怎么简便

答

12.5 × 9.8 - 4.9 × 5
= 12.5 × 2 × 4.9 - 4.9 × 5
= 25 × 4.9 - 4.9 × 5
= 4.9 × (25 - 5)
= 4.9 × 20
= 98

12.5*9.8-4.9*5怎么简便