2/3+2/8+2/15+2/24+2/35+2/48+2/63+2/80=过程详细点

2/3+2/8+2/15+2/24+2/35+2/48+2/63+2/80=过程详细点
2/3+2/8+2/15+2/24+2/35+2/48+2/63+2/80=
过程详细点

2/3+2/8+2/15+2/24+2/35+2/48+2/63+2/80=过程详细点
2/3+2/8+2/15+2/24+2/35+2/48+2/63+2/80
=2/(1*3) + 2/(2*4) + 2/(3*5) + 2/(4*6) + 2/(5*7) + 2/(6*8) + 2/(7*9) + 2/(8*10)
=1/1 - 1/3 + 1/2 - 1/4 + 1/3 - 1/5 + 1/4 - 1/6 + 1/5 - 1/7 + 1/6 - 1/8 + 1/7 - 1/9 + 1/8 - 1/10
=1 + 1/2 - 1/9 - 1/10
=1 + 45/90 - 10/90 - 9/90
=1 + 26/90
=1又90分之26