10 2/3-2 5/8*(4 1/2-1 5/6) = 3 2/3
1) 4 1/2 - 1 5/6 = 9/2 - 11/6 = 27/6 - 11/6 = 16/6 = 8/3
2) 2 5/8 * 8/3 = 21/8 * 11/ 3 = 7
3) 10 2/3 - 7 = 3 2/3
