7.8*1990+78简便计算怎么算?

分类: 作业答案 • 2021-12-28 14:50:17

问题描述：

7.8*1990+78简便计算怎么算?

答

7.8 × 1990 + 78
= 7.8 × 1990 + 7.8 × 10
= 7.8 × (1990 + 10)
= 7.8 × 2000
= 15600