1) 8/21 - 11/5 = (85 - 1121) / (21*5) = (40 - 231) / 105 = -191 / 105
2) -5/18 - 7/8 = (-58 - 718) / (18*8) = (-40 - 126) / 144 = -166 / 144 = -83 / 72
3) 17/20 + 7/30 = (1730 + 720) / (20*30) = (510 + 140) / 600 = 650 / 600 = 13 / 12
4) -9/14 42/81 = (-942) / (14*81) = -378 / 1134 = -2 / 6 = -1 / 3
5) (6/1) / 12 - (10/3) / 16 = 6/12 - 10/16 = 1/2 - 5/8 = 4/8 - 5/8 = -1/8
1) 8/21 - 11/5 = (85 - 1121) / (21*5) = (40 - 231) / 105 = -191 / 105
2) -5/18 - 7/8 = (-58 - 718) / (18*8) = (-40 - 126) / 144 = -166 / 144 = -83 / 72
3) 17/20 + 7/30 = (1730 + 720) / (20*30) = (510 + 140) / 600 = 650 / 600 = 13 / 12
4) -9/14 42/81 = (-942) / (14*81) = -378 / 1134 = -2 / 6 = -1 / 3
5) (6/1) / 12 - (10/3) / 16 = 6/12 - 10/16 = 1/2 - 5/8 = 4/8 - 5/8 = -1/8