1) (6 1/4 - 4 1/8) * 4 + 3 1/3 : 2 1/2 = (6 2/8 - 4 1/8) * 4 + 10/3 : 5/2 = 2 1/8 * 4 + 10/3 * 2/5 = 8 4/8 + 4/3 = 8 1/2 + 1 1/3 = 8 3/6 + 1 2/6 = 9 5/6.
2) (2 4/9 + 1 1/6) * 1 4/5 - 3 1/9 : 2 1/3 = (2 8/18 + 1 3/18) * 9/5 - 28/9 : 7/3 = 3 11/18 * 9/5 - 28/9 * 3/7 = 65/18 * 9/5 - 4/3 = 13/2 - 4/3 = 39/6 - 8/6 = 31/6 = 5 1/6.
3) (2 - 1 7/12) : (3/8 - 1/6) * 3 1/4 = 1 5/12 : (9/24 - 4/24) * 13/4 = 17/12 : 5/24 * 13/4 = 17/12 * 24/5 * 13/4 = 221/10 = 22 1/10.
4) (7/10 - 2/5) * (1/4 + 5/6) : 6 1/2 = (7/10 - 4/10) * (6/24 + 20/24) : 6 1/2 = 3/10 * 26/24 : 13/2 = 3/10 * 26/24 * 2/13 = 3/10.