Activity 01
Number Line Hops: Backwards Relay
Mark a giant number line on the floor from 0 to 20. In pairs, students start at a called number like 14 and hop back the required amount, such as 3 steps for 14-3. Partners verify the landing spot and record the answer. Switch roles after five problems.
Compare counting on with counting back for different types of problems.
Facilitation TipDuring Number Line Hops: Backwards Relay, mark each hop with a clear verbal count to reinforce rhythm and direction.
What to look forPresent students with a set of subtraction problems (e.g., 17 - 5, 13 - 3, 19 - 7). Ask them to solve each using counting back and show their work on a mini-whiteboard or paper, circling their final answer.
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Activity 02
Bead String Slides: Subtraction Stations
Provide bead strings to small groups. Call out problems like 17-6; students slide beads back from the start number, counting aloud. Groups check answers with a partner before rotating to draw the process on mini whiteboards.
Construct a subtraction problem that is best solved by counting back.
Facilitation TipIn Bead String Slides: Subtraction Stations, encourage students to slide beads one at a time while whispering the count to maintain pace.
What to look forPose the question: 'When is it best to count back to solve a subtraction problem, and when might counting on be easier?' Encourage students to give examples and explain their reasoning, referencing problems they have solved.
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Activity 03
Toy Take-Away Dramas: Story Pairs
Pairs use 20 counters or toys to act out teacher-provided stories, like 'Start with 15 apples, eat 4'. One child sets up and counts back while the partner narrates and confirms. Pairs then invent and solve their own story.
Justify the importance of knowing how to count back accurately.
Facilitation TipFor Toy Take-Away Dramas: Story Pairs, ensure every student takes a turn as the actor and the counter to build shared understanding.
What to look forGive each student a card with a subtraction problem (e.g., 14 - 6). Ask them to write the answer and then one sentence explaining how they used counting back to find it. Collect these to gauge individual understanding of the strategy.
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Activity 04
Counting Back Bingo: Whole Class
Distribute bingo cards with numbers 0-20. Call subtractions like 10-3=7; students mark the answer if on their card and count back aloud to confirm. First full line wins a group cheer.
Compare counting on with counting back for different types of problems.
Facilitation TipIn Counting Back Bingo: Whole Class, pause after each call to let students whisper the count to themselves before marking their boards.
What to look forPresent students with a set of subtraction problems (e.g., 17 - 5, 13 - 3, 19 - 7). Ask them to solve each using counting back and show their work on a mini-whiteboard or paper, circling their final answer.
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Generate Complete Lesson→A few notes on teaching this unit
Teach counting back as a purposeful strategy, not just a sequence of numbers. Model consistent phrasing like, ‘Start at 15, count back 3: fourteen, thirteen, twelve’ to anchor the process. Avoid letting children default to counting on for every problem; instead, guide them to compare both strategies and decide which fits the context. Research shows that physical movement and peer explanation strengthen retention, so incorporate both throughout.
By the end of these activities, students will solve subtraction problems up to 20 by counting back accurately and consistently. They will choose counting back when appropriate, explain their process, and demonstrate confidence with teen numbers and larger subtrahends.
Watch Out for These Misconceptions
During Number Line Hops: Backwards Relay, watch for students rolling the number cube and counting back from 10, regardless of the starting number on their card.
Have them place their counter directly on the starting number and say the number aloud before beginning their relay, reinforcing the habit of starting where the problem begins.
During Bead String Slides: Subtraction Stations, watch for students sliding multiple beads at once or skipping numbers when the subtrahend is large.
Ask them to slide one bead per whispered count and tap the bead with their finger to anchor each step, building accuracy with larger subtrahends.
During Toy Take-Away Dramas: Story Pairs, watch for students counting on instead of counting back during their dramatic subtraction scenes.
Prompt them to start with the larger number in their story and physically remove the toys one by one while counting backwards aloud, aligning the action with the strategy.
Methods used in this brief