(-1999)*1999/2000

问题描述:

(-1999)*1999/2000

﹙﹣1999﹚×1999/2000
=﹙﹣2000+1﹚×1999/2000
=﹙﹣2000﹚×1999/2000+1×1999/2000
=﹣1999+1999/2000
=﹣1998又1/2000.