1又1/20+2又1/30+3又1/42+4又1/56+5又1/72+6又1/90+7又1/110+8又1/132=?
问题描述:
1又1/20+2又1/30+3又1/42+4又1/56+5又1/72+6又1/90+7又1/110+8又1/132=?
答
=1+2+3+4+5+6+7+8+1/20+1/30+.+1/132
=36+1/4-1/5+1/5-1/6+1/6-1/7.+1/11-1/12
=36+1/4-1/12
=36+1/6