1又2/1-6/5+12/7-20/9+30/11-42/13+56/15简算

问题描述:

1又2/1-6/5+12/7-20/9+30/11-42/13+56/15简算

1又2/1-6/5+12/7-20/9+30/11-42/13+56/15
=1+2/1-2/1-3/1+3/1+4/1-4/1-5/1+5/1+6/1-6/1-7/1+7/1+8/1
=1+8/1
=1又8/1

1又2/1-6/5+12/7-20/9+30/11-42/13+56/15=(1+1/2)-(1/2+1/3)+(1/3+1/4)-(1/4+1/5)+(1/5+1/6)-(1/6+1/7)+(1/7+1/8)=1+1/2-1/2-1/3+1/3+1/4-1/4-1/5+1/5+1/6-1/6-1/7+1/7+1/8=1+1/8=1又1/8