Which subtraction expression does the number line model show? A number line with arrowed movements. Start at 0 on the right and move 4 units to the left. From that number, move 9 more units to the left. End at negative 13. –13 + 4 –4 – 13 –4 – 9 –4 + 9ne with arrowed movements. Start at 0 on the right and move 4 units to the left. From that number, move 9 more units to the left. End at negative 13.