1+1/2+1/6+1/12+1/20+1/30+1/42+1/56+……+1/132
=1+1/2+(1/2-1/3)+(1/3-1/4)+(1/4-1/5)+...+(1/11-1/12)
=1+1/2+1/2-1/3+1/3-1/4+1/4-1/5+...-1/11+1/11-1/12
=+1/2+1/2-1/12
=1又11/12