2(3/5) : 6(1/15) + 1(1/14) - (139/73) * (5(5/7) - 5(1/16)) =
13/5 : 91/15 + 15/14 - (139/73) * (40/7 - 81/16) =
13/5 * 15/91 + 15/14 - (139/73) * (640/112 - 567/112) =
3/1 * 3/7 + 15/14 - (139/73) * (73/112) =
9/7 + 15/14 - 139/112 = (9*16 + 15*8 - 139) / 112 = (144 + 120 - 139) / 112 = 125/112 = 1(13/112)