Gregory wants to read at least 50 pages this month. He has already read 13 pages so far. Which number line represents how many pages Gregory needs to read for the rest of the month to reach his goal?

The number line representing how many pages Gregory needs to read for the rest of the month in order to reach his goal should start at 37 (50 - 13) and go up from there.

It would look like this:
37 - 38 - 39 - 40 - 41 - 42 - 43 - 44 - 45 - 46 - 47 - 48 - 49 - 50.