5/7 - 1/2 = 10/14 - 7/14 = 3/14
6 2/3 + 7 3/4 = 6 + 2/3 + 7 + 3/4 = 13 + 11/12 = 13 11/12
14/9 × 12/21 = (2 × 7) / (3 × 3) × (4 × 3) / (7 × 3) = 14/27 × 12/21 = 168/567 = 56/189 = 8/27
5/7 - 1/2 = 10/14 - 7/14 = 3/14
6 2/3 + 7 3/4 = 6 + 2/3 + 7 + 3/4 = 13 + 11/12 = 13 11/12
14/9 × 12/21 = (2 × 7) / (3 × 3) × (4 × 3) / (7 × 3) = 14/27 × 12/21 = 168/567 = 56/189 = 8/27