1/3+3/4+2/5+5/7+7/8+9/20+10/21+11/24+19/35 =1/3+3/4+2/5+5/7+7/8+(4/20+5/20)+(3/21+7/21)+(3/24+8/24)+(5/35+14/35) =1/3+3/4+2/5+5/7+7/8+(1/5+1/4)+(1/7+1/3)+(1/8+1/3)+(1/7+2/5) =1/3*3+(3/4+1/4)+(2/5+1/5+...