Counting Back
Subtract by counting back
To take away, count back on the number line. Start at 9, count back 4!
012345678910
Start at 9, count back 4: 8, 7, 6, 5!
To subtract, count back on the number line. 9 − 4: start at 9, hop back 4 → land on 5. Counting back is the opposite of counting on for adding!