-99 ×1999=?简便运算（要有过程）.

分类: 作业答案 • 2021-12-19 11:34:25

问题描述：

答

=-(100-1)×1999
=-(199900-1999)
=-(199900-2000+1)
=-197901

答

-99 ×1999
=（-100+1）×1999
= -199900+1999
= -199900+2000-1
= -197901

答

-99×1999
=（-100+1）×1999
=-199900+1999
=-199900+2000-1
=-197999