(-1999)*1999/2000
问题描述:
(-1999)*1999/2000
答
﹙﹣1999﹚×1999/2000
=﹙﹣2000+1﹚×1999/2000
=﹙﹣2000﹚×1999/2000+1×1999/2000
=﹣1999+1999/2000
=﹣1998又1/2000.