1. The problem asks: "What does this number line go up in?" which means we need to find the increment between each labeled tick mark. 2. To find the increment, look at the difference between two consecutive numbers on the number line. 3. The number line shows numbers: 0, 50, 100, 150, 200, 250, 300, 350, 400. 4. Calculate the difference between any two consecutive numbers, for example, $50 - 0$. 5. This difference represents the step size or increment of the number line. 6. Understanding increments helps in reading and interpreting number lines correctly. This explanation guides you to find the increment without directly solving it.