2/3+2/8+2/15+2/24+2/35+2/48+2/63+2/80=?急啊
问题描述:
2/3+2/8+2/15+2/24+2/35+2/48+2/63+2/80=?急啊
要求有过程,用简便算法算,最好符合5年级的做法,不要太难
答
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 +...