3/8 + 4/9 = (3 * 9 + 4 * 8) / (8 * 9) = (27 + 32)/72 = 59/72
7/12 - 3/8 = (7 * 2 - 3 * 3) / 24 = (14 - 9)/24 = 5/24
2 5/8 + 1 3/10 = 2 25/40 + 1 12/40 = 3 37/40
6 7/10 - 4 5/12 = 6 42/60 - 4 25/60 = 2 17/60
3/8 + 4/9 = (3 * 9 + 4 * 8) / (8 * 9) = (27 + 32)/72 = 59/72
7/12 - 3/8 = (7 * 2 - 3 * 3) / 24 = (14 - 9)/24 = 5/24
2 5/8 + 1 3/10 = 2 25/40 + 1 12/40 = 3 37/40
6 7/10 - 4 5/12 = 6 42/60 - 4 25/60 = 2 17/60