18/53+9/35+22/53+17/35+20/53+6/35

18/53 + 9/35 + 22/53 + 17/35 + 20/53 + 6/35 = (18/53 + 22/53 + 20/53) + (9/35 + 17/35 + 6/35)

= (18 + 22 + 20) / 53 + (9 + 17 + 6) / 35 = 60/53 + 32/35 = (60 * 35 + 32 * 53) / (53 * 35) =

= [4 * (15 * 35 + 8 * 53) ] / (53 * 35) = [4 * (525 + 424) ] / (53 * 35) = 3796/1855 = 2 86/1855.