Mathematics · Grade 2

Active learning ideas

Adding Two-Digit Numbers (No Regrouping)

Hands-on activities let students physically separate steps, making two-step problems clearer. By acting out scenarios or cutting apart stories, learners slow down to plan before calculating, which builds confidence and accuracy in solving whole-number operations.

• Ontario Curriculum Expectations
• 2.NBT.B.5

• 15–35 min
• Pairs → Whole Class
• 3 activities

Activity 01

• Inquiry Circle
• 35 min · Small Groups

Inquiry Circle: Story Surgeons

Give groups a long word problem printed on a strip of paper. They must use scissors to 'perform surgery,' cutting the problem into the first step and the second step. They glue these onto a poster and solve each part separately.

Explain why we add the ones digits first when adding two-digit numbers.

Facilitation Tip

During Story Surgeons, have students highlight the first action in one color and the second in another to make the steps visually distinct.

What to look for

Present students with a worksheet containing 3-4 addition problems (e.g., 32 + 15, 41 + 27). Ask them to solve each problem using a place value chart and then write the answer. Observe if they correctly align the ones and tens columns.

• Analyze
• Evaluate
• Create
• Self-Management
• Self-Awareness

Activity 02

• Role Play
• 25 min · Small Groups

Role Play: The Problem Solvers' Agency

One student acts as a 'client' with a complex problem (e.g., 'I had 20 stickers, gave 5 to Sam, and then bought 10 more'). The other students are 'agents' who must draw a diagram to show the two steps and provide the final answer.

Design a visual model to show 23 + 45.

Facilitation Tip

In The Problem Solvers' Agency, assign roles like 'giver' and 'receiver' so students physically model the problem before they calculate.

What to look for

Pose the question: 'Imagine you are adding 53 + 24. Why is it important to add the 3 and the 4 first?' Facilitate a class discussion where students explain their reasoning using terms like 'ones' and 'tens'.

• Apply
• Analyze
• Evaluate
• Social Awareness
• Self-Awareness

Activity 03

• Think-Pair-Share
• 15 min · Pairs

Think-Pair-Share: What's the Hidden Question?

Present a two-step problem and ask students to find the 'hidden question' that must be answered first. For example, in 'I bought two $5 toys and gave the clerk $20,' the hidden question is 'How much did the toys cost altogether?' Pairs share their hidden questions with the class.

Compare adding tens and ones separately to adding numbers vertically.

Facilitation Tip

For What's the Hidden Question?, pause after reading and ask, 'What do we know so far?' to push thinking before solving.

What to look for

Give each student a card with a visual model (e.g., base-ten blocks showing 23 and 45). Ask them to write the addition sentence represented by the blocks and calculate the sum. Collect these to check for understanding of visual representation and calculation.

• Understand
• Apply
• Analyze
• Self-Awareness
• Relationship Skills

A few notes on teaching this unit

Teach place value first with base-ten blocks so students can see why 3 + 4 comes before adding tens. Avoid rushing to abstract symbols; anchor every calculation in concrete models. Research shows students need to verbalize their steps aloud, so have them explain their thinking to peers or a teacher while working.

Students will explain each step of their process, use place value tools correctly, and show their work clearly. By the end, they will solve two-step problems without skipping a step, explaining why each operation is needed.

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Watch Out for These Misconceptions

• During Story Surgeons, watch for students who circle one number and stop without solving the second part of the problem.

  Have them reread the story and physically separate the problem into two parts using their highlighted colors, then solve each part one at a time.

• During The Problem Solvers' Agency, watch for students who add all numbers together regardless of the scenario's context.

  Prompt them to act out the scenario first, asking, 'Is this person getting more or giving away?' to clarify whether to add or subtract at each step.

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Methods used in this brief

• Inquiry Circle
• Role Play
• Think-Pair-Share