等于0.954545455
1/2+2/8+3/28+4/77+5/176+6/352=1/2+1/4+3/28+4/77+10/352+6/352=3/4+3/28+4/77+16/352=21/28+3/28+4/77+1/22=24/28+4/77+1/22=6/7+4/77+1/22=66/77+4/77+1/22=70/77+1/22=10/11+1/22=20/22+1/22=21/22