4/3+16/15+36/35+64/63+100/99+144/143=6+（1/3+1/15+1/35+1/63+1/99+1/143）=6+1/2(1-1/3+1/3-1/5+1/5-1/7+1/7-1/9+1/9-1/11+1/11-1/13)=6+1/2(1-1/13)=6+6/13=84/13