Read the interval first
Find the first and last labelled numbers. Then count the equal jumps between neighbouring marks to identify the step size.
For example, a line from 0 to 20 with ten equal jumps increases by 2 at each tick. Starting at 0, six jumps land on 12. Count the jumps instead of guessing the marked value by eye.
Keep every step the same
Move from the start one tick at a time. The same step applies across the whole line, even when only the endpoints are labelled.
If a child names the marked tick incorrectly, ask them to say the number at each earlier tick aloud. The focused practice changes the interval and labels while keeping the equal-step rule.