1/2-1/6-1/12-1/20-1/30-1/42-···-1/132
1/20+1/30+1/42······+1/132 简算 帮帮忙!
1/2+1/6+1/12+1/20+1/30······+1/90+1/110=( )
1/6+1/12+1/20+1/30+1/42+1/56怎么简便计算?19/99+19/99×2+19/99×3+···
1/6+1/12+1/20+1/30+···+1/(2005乘2006)
简算 1/2+1/6+1/12+······+1/9900
1+1/2+1/6+1/12+1/20+1/30+1/42+1/56+.1/132=
1+1/2+1/6+1/12+20/1+30/1+42/1+56/1+...+1/132
已知5/6=1/2+1/3,7/12=1/3+1/4,9/20=1/4+1/5······
1/6+1/12+1/20+1/30+···+1/2009*2010(完整的 嘻)
1/6+1/12+1/20+1/30+1/42+……+1/132等于多少
计算2分之1+6分之1+12分之1+20分之1+······+90分之1
1/2+1/6+1/12+······+1/9900埃及分数怎样算