4 5/9 + 7 1/6 = 4 10/18 + 7 3/18 = 11 13/18, 6 11/12 + 8 13/18 = 6 33/36 + 8 26/36 = 14 59/36 = 15 23/36
4 5/9 + 7 1/6 = 4 10/18 + 7 3/18 = 11 13/18, 6 11/12 + 8 13/18 = 6 33/36 + 8 26/36 = 14 59/36 = 15 23/36