Mathematics · Grade 2

Active learning ideas

Addition Strategies: Making Ten and Doubles

Active learning helps students connect abstract number relationships to concrete experiences, which is essential for grasping the inverse relationship between addition and subtraction. This topic benefits from hands-on exploration because students need to physically manipulate numbers to see how making ten and doubles strategies simplify calculations and reduce memory load.

• Ontario Curriculum Expectations
• 2.OA.B.2

• 15–25 min
• Pairs → Whole Class
• 3 activities

Activity 01

• Role Play
• 20 min · Pairs

Role Play: The Number Reverser

One student acts as the 'Adder' and creates a problem with blocks (e.g., 5+3). The partner acts as the 'Undoer' and must physically take away the added blocks to show the subtraction fact. They then switch roles to see how many facts they can 'undo' in five minutes.

Analyze how 'making ten' simplifies addition problems.

Facilitation Tip

For The Subtraction Mystery, circulate and listen for students who justify their missing addend solutions by referencing known addition facts, as this indicates they are bridging operations.

What to look for

Present students with a series of addition problems (e.g., 9+3, 7+7, 8+5, 6+7). Ask them to write down the strategy they used for each problem (Making Ten, Doubles, or Near Doubles) and the answer. Review their choices to see if they are applying the strategies appropriately.

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

Activity 02

• Inquiry Circle
• 25 min · Small Groups

Inquiry Circle: Fact Family Houses

Small groups are given three numbers (e.g., 12, 7, 5). They must work together to find all four equations that live in that 'house.' They present their house to the class, explaining why no other numbers are allowed to move in.

Compare the efficiency of using doubles versus counting on for certain sums.

What to look for

Pose the question: 'How does knowing 5+5=10 help you solve 5+6?' Facilitate a class discussion where students explain their reasoning, using terms like 'making ten' or 'near doubles'. Encourage students to share their thought processes with a partner before sharing with the whole group.

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

Activity 03

• Think-Pair-Share
• 15 min · Pairs

Think-Pair-Share: The Subtraction Mystery

Ask students: 'If I have a total and I take away one part, what am I left with?' Pairs use part-part-whole mats to test this with different numbers and then share their 'rule' for subtraction with the class.

Explain why knowing 6+6 helps you solve 6+7.

What to look for

Give each student a card with an addition problem, such as 7+5. Ask them to write two different ways to solve it: one using the 'making ten' strategy and one using the 'doubles' or 'near doubles' strategy. They should also write the final sum for each method.

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

A few notes on teaching this unit

Teachers should avoid presenting addition and subtraction as separate skills. Instead, use consistent language like 'parts' and 'whole' across all activities so students see the operations as interconnected. Research suggests that students who verbalize their strategies while solving problems develop stronger number sense and retention.

Successful learning looks like students confidently applying making ten and doubles strategies to solve addition problems. They should also articulate how these strategies connect to subtraction using terms like 'fact families' and 'part-part-whole'. By the end, students will fluently switch between operations to find unknown values.

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Watch Out for These Misconceptions

• During the Number Reverser role play, watch for students who reverse the order of numbers when acting out subtraction scenarios, such as giving 3 candies when the problem is 5 - 3.

  Prompt students to use the counters to model the starting amount first, then physically remove the second amount, emphasizing that the order of removal matches the problem.

• During the Think-Pair-Share activity, watch for students who see addition and subtraction as unrelated and rely only on addition facts to solve missing addend problems like 8 + ? = 12.

  Have students use the counters from the Fact Family Houses to model 12 as the whole, then separate 8 as one part to find the missing part, explicitly naming it as subtraction (12 - 8).

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Methods used in this brief

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