987+876+765+654+543+432+321+210简便计算
问题描述:
987+876+765+654+543+432+321+210简便计算
答
990-3+880-4+770-5+660-6+550-7440-8330-9+220
=990+880+770+660+550+440+330-3-4-5-6-7-8-9
答
990-3+880-4+770-5+660-6+550-7440-8330-9+220
=990+880+770+660+550+440+330-3-4-5-6-7-8-9
=如此