Mathematics · Primary 2

Active learning ideas

Word Problems: Addition and Subtraction

Students learn best by doing, especially with word problems where translating words into numbers can feel abstract. Using physical and social tools lets children test their thinking in real time, turning 'I'm not sure' into 'Let me show you.' Concrete models give students a way to catch mistakes before they become habits.

• MOE Syllabus Outcomes
• MOE: Numbers and Algebra - P2
• MOE: Problem Solving - P2

• 25–40 min
• Pairs → Whole Class
• 4 activities

Activity 01

• Plan-Do-Review
• 30 min · Pairs

Manipulative Bars: Block Models

Pairs read a word problem, then use unifix cubes to build bar models showing quantities and relationships. They label parts, solve step-by-step, and write the equation. Pairs swap models with neighbors to verify solutions.

How does a bar model help us understand the relationship between quantities in a word problem?

Facilitation Tip

During Manipulative Bars, ask students to label each bar with the story’s numbers before writing any equations.

What to look for

Present students with a 1-step word problem. Ask them to draw a bar model, write the number sentence, and solve. For example: 'Sarah had 250 marbles. She won 120 more. How many marbles does she have now?'

• Remember
• Apply
• Analyze
• Self-Management
• Decision-Making
• Self-Awareness

Activity 02

• Plan-Do-Review
• 40 min · Small Groups

Role-Play Scenarios: Act and Model

Small groups pick props like toys or drawings to act out problems, such as buying fruit. One student narrates while others build bar models on paper during the skit. Groups solve and present their models to the class.

What clue words tell us whether to add or subtract?

Facilitation Tip

In Role-Play Scenarios, freeze the action after each step and ask, 'What does this part of the story mean?' before modeling it with blocks.

What to look for

Give students a 2-step word problem, such as: 'There were 300 red balloons and 250 blue balloons. 100 balloons popped. How many balloons are left?' Ask them to draw a bar model for the first step, write the number sentence, and then solve the second step, showing both calculations.

• Remember
• Apply
• Analyze
• Self-Management
• Decision-Making
• Self-Awareness

Activity 03

• Plan-Do-Review
• 35 min · Small Groups

Clue Hunt Relay: Word Cards

Divide class into teams. Scatter cards with clue words and problems around the room. One student per team grabs a card, returns to build a bar model with group input, solves it, then tags the next teammate.

How do we check that our answer makes sense in the context of the problem?

Facilitation Tip

For Clue Hunt Relay, hide clue words in different colors and have teams sort them into 'Addition,' 'Subtraction,' or 'Both' before solving.

What to look for

Pose a word problem with ambiguous clue words. For example: 'John has 50 apples. Mary has 20 more apples than John. How many apples do they have together?' Ask students: 'What clue words help you decide what to do first? How can you check if your answer is reasonable?'

• Remember
• Apply
• Analyze
• Self-Management
• Decision-Making
• Self-Awareness

Activity 04

• Gallery Walk
• 25 min · Small Groups

Gallery Walk: Peer Review

Students solve individual problems with bar models on chart paper and post them. In small groups, they walk the gallery, check if models match problems and answers make sense, then suggest improvements.

How does a bar model help us understand the relationship between quantities in a word problem?

Facilitation Tip

During Check-It Gallery Walk, provide a checklist with 'Does the bar match the story?' and 'Can a peer explain each step?' to guide reviewers.

What to look for

Present students with a 1-step word problem. Ask them to draw a bar model, write the number sentence, and solve. For example: 'Sarah had 250 marbles. She won 120 more. How many marbles does she have now?'

• Understand
• Apply
• Analyze
• Create
• Relationship Skills
• Social Awareness

A few notes on teaching this unit

Start with hands-on tools so students see how quantities combine or compare before moving to symbols. Avoid teaching clue words as rules, because words like 'more' can appear in both addition and subtraction situations. Instead, model flexible thinking by asking, 'What is changing here?' to focus on the story’s structure. Use peer talk to uncover misconceptions early and refine understanding together.

By the end of these activities, students will confidently draw bar models that match the problem story and choose the correct operation without relying on clue words alone. They will explain their steps, listen to peers, and revise their work when something doesn’t fit the story. Clear bar models and number sentences show their understanding.

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Watch Out for These Misconceptions

• During Manipulative Bars, watch for students who draw bars based on clue words instead of the story’s meaning.

  Ask them to retell the story while pointing to each bar, then adjust the model so it matches their words rather than the clue word they chose.

• During Role-Play Scenarios, watch for students who act out the first part of a 2-step problem and stop there.

  Pause the role-play after the first step and ask, 'What happens next in the story?' Have them add new bars or blocks to show the second step before writing any equations.

• During Clue Hunt Relay, watch for students who sort clue words into 'Add' or 'Subtract' without considering the problem’s context.

  Have teams swap problems with another group and explain why their clue words led to a specific operation, using the story’s details to justify their choice.

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Methods used in this brief

• Plan-Do-Review
• Gallery Walk