Start on the first number, hop back, and write where you land. Each of the five problems has its own number line from 0 to 10, and a worked example at the top shows 9 − 3 as three little hops back to 6.
Counting back is one of the first real strategies for subtraction, and drawing the hops makes it visible. A child can see that 10 − 4 means four jumps, and that the answer is simply where the last one lands.
The numbers stay within 10 so the strategy stays in focus, which makes this a good first number line page before moving to lines that run to 20.