1/3+1/6+1/10+1/15+1/21+1/28+1/36+1/45简便计算

1/3+1/6+1/10+1/15+1/21+1/28+1/36+1/45简便计算
1/3+1/6+1/10+1/15+1/21+1/28+1/36+1/45简便计算

1/3+1/6+1/10+1/15+1/21+1/28+1/36+1/45简便计算
1/3+1/6+1/10+1/15+1/21+1/28+1/36+1/45 =1/3+1/2*3+1/2*5+1/3*5+1/3*7+1/4*7+1/4*9+1/5*9 =3/2*3+5/2*3*5+7/3*4*7+9/4*5*9 =1/2+1/6+1/12+1/36 =（18+6+3+1）/36 =19/18