9876乘9876减9875乘9877简便

问题描述:

9876乘9876减9875乘9877简便

9876×9876-9875×9877
=﹙9875+1﹚×9876-9875×﹙9876+1﹚
=9875×9876-9876×1-9875×9876+9875×1
=9876-9875
=1