(3 - 1 7/15) * 5 + (2 - 1 5/16) * 4 = 10 5/12
1) 3 - 1 7/15 = 2 15/15 - 1 7/15 = 1 8/15
2) 2 - 1 5/16 = 1 16/16 - 1 5/16 = 11/16
3) 1 8/15 * 5 = 23/15 * 5 = 23/3 = 7 2/3
4) 11/16 * 4 = 11/4 = 2 3/4
5) 7 2/3 + 2 3/4 = 7 8/12 + 2 9/12 = 9 17/12 = 10 5/12