4 + 5 1/4 = 9 1/4,
1 2/9 + 3 1/3 = 1 2/9 + 3 3/9 = 4 5/9,
1 3/5 + 2 2/3 = 1 9/15 + 2 10/15 = 3 19/15 = 4 4/15,
5 3/4 - 2 = 3 3/4,
3 - 5/7 = 2 7/7 - 5/7 = 2 2/7,
4 - 1 7/9 = 3 9/9 - 1 7/9 = 2 2/9,
3 2/5 - 3/5 = 2 7/5 - 3/5 = 2 4/5,
4 1/3 - 1 1/2 = 4 2/6 - 1 3/6 = 3 8/6 - 1 3/6 = 2 5/6