Grade 2 · addition and subtraction
Subtract with a number line
Show subtraction by moving back along a number line, counting each jump once.
Try a little together. Every step is optional, and you can stop whenever you need.
Show it
Get ready: Paper, a pencil and a counter. Draw equally spaced marks from 0 to 10.
Move one step at a time
0 jumps back from 8. The counter is on 8.
8 − 3 = 5
- Put a counter on 8. Say: “We have eight. We are taking away three.”
- Move back one space to 7, then to 6, then to 5. Count the jumps: one, two, three.
- Say: “Three jumps back from eight lands on five.” Write 8 − 3 = 5 and check by taking three away from eight objects.
“Where do we start? How many jumps will we make? Where did we land?”
Try 7 − 2 and 9 − 3. One person moves the counter; the other counts the jumps. Swap roles.
What to notice and a response to try
The child counts the starting mark as the first jump and lands on 6.
Keep the counter on eight before counting. Say “one” only when it moves to seven. Draw one arc for each space crossed so the jumps stay visible.
Keep going with objects or paper
Draw a number line from 0 to 10. Put a block on eight and move it back three spaces. Make up another take-away story together.
This works without a screen, an account or a printer.
Or play Subtraction Submarine
Turn your device sideways, then choose Quick Start for subtraction within 10. Keep your paper number line beside you. Pause the game whenever you want to show the jumps.
Games use a free adult account. When you’re ready, choose “Back to our idea” in the game. Finishing the game is optional.
Play Subtraction Submarine →Use a classroom tool together
When ready for two-digit examples, choose subtraction in the Number Line tool. Point out the starting number and count the spaces crossed. For small numbers, use the demonstration above or your paper line.
Explore larger numbers on Number Line →Free, no sign-in. Come back to this guide when you’re ready.
Draw a fresh number line on paper. Ask the child to show 10 − 2 and explain what the start, jumps and landing number mean.
Listen and look for
The child starts at ten, makes two jumps back, and explains why eight is the amount left. A drawing or spoken explanation is useful alongside game answers.
Let them point, move objects, draw or explain aloud. One example starts a conversation; it does not establish mastery.
A good place to pause
Next time, try the idea with different objects or numbers. Notice how your child shows their thinking.
Draw a number line from 0 to 10. Put a block on eight and move it back three spaces. Make up another take-away story together.
Only your place in this guide is remembered. No answer or judgment about your child is saved.
Need an easier example or a break?
Use five objects and take one away. Match that action to one jump back from 5 to 4 on the line.
Try one example yourself while your child watches. Keep fingers, objects and drawings available. If it feels frustrating, stop and return to something familiar another day.
Ready for more?
For 9 − 6, compare six jumps back from nine with counting up from six to nine. Explain how both methods show a difference of three.
Use it with your class
One shared screen is enough. Give pairs objects or paper so everyone can take part.
- Show eight objects and remove three. Ask children to explain what changed.
- Model the same action on a number line. Pairs take turns choosing a start and moving back one, two or three spaces.
- Compare a counter model and a number-line drawing. Finish with 10 − 2 on paper.
Curriculum connection: Gr 2 · N9 in the NB 2009 guide. This activity practises part of the outcome; it is not an assessment of the whole outcome.
Take the same idea home
Share this free guide or print a short card for families. The link contains only the topic, with no names or progress attached.
Ready-to-share family note
We’re exploring: Subtract with a number line. Show subtraction by moving back along a number line, counting each jump once. Try this together at home: Draw a number line from 0 to 10. Put a block on eight and move it back three spaces. Make up another take-away story together. You can use objects or paper, and stop whenever you need. Free guide: https://mraube.ca/learn/subtract-on-a-number-line