1又2/1+2又6/1+3又12/1+4又20/1+5又30/1+6又42/1+...+11又132/1等于几?
问题描述:
1又2/1+2又6/1+3又12/1+4又20/1+5又30/1+6又42/1+...+11又132/1等于几?
答
1又2/1+2又6/1+3又12/1+4又20/1+5又30/1+6又42/1+...+11又132/1
=1+1/2+2+1/6+3+1/12+4+1/20+5+1/30+6+1/42+7+1/56+8+1/72+9+1/90+10+1/110+11+1/132
=66+1-1/2+1/2-1/3+1/3-1/4+.+1/10-1/11+1/11-1/12
=66+1-1/12
=66+11/12
=66又12分之11