To solve the subtraction problem expressed by the number line, we start at five-sixths (5/6) and move three tick marks to the left.
Each tick mark represents one-sixth (1/6). Therefore, moving left three tick marks means we subtract three-sixths (3/6) from five-sixths (5/6):
5/6 - 3/6 = (5 - 3)/6 = 2/6
So, the solution to the subtraction problem is:
2 6