Building Addition Strategies

Overview

In this lesson, students use known number facts and place value to solve addition problems up to 100. They practise specific strategies—making ten, using doubles, and counting on—then choose the most helpful method for each sum.

Learning intentions

• WALT use known facts (like making ten and doubles) to solve addition problems up to 100.
• WALT explain how our strategy helps us find the total efficiently.
• WALT choose between strategies (making ten, doubles, counting on) to match the numbers.

Success criteria

• I can solve additions up to 100 using a strategy that makes sense for the numbers.
• I can use a known fact (e.g., 9 + 1, 5 + 5) to help me add.
• I can explain (or show) how I counted on or how I made ten.
• I can check my answer by using another strategy or a different representation.

Curriculum links

• Number — operations: Solving multi-step addition and subtraction problems involving numbers up to 100 (used in today’s single-step additions with strategy and justification).
• Number — operations: Number facts can be derived from known facts using place value (e.g., tens and ones; turning 34 + 6 into 40).
• Mathematics and Statistics competencies: Reasoning (explaining strategies), Using language/symbols (number sentences and explanations), and Participating and contributing (sharing methods respectfully).

Lesson structure (60 minutes)

1. 0–5 min · Hook (quick mental start). Teacher writes: “34 + 6 =?” and asks: “What could we do first—make ten, use doubles, or count on?” Students share one idea with a partner.

2. 5–15 min · Direct teaching: model 3 strategies. Teacher demonstrates and names strategies, using brief “think-alouds”:

• Making ten (first with ones): For 34 + 6, “I need 4 more to make 10 ones. 6 = 4 + 2, so 34 + 4 = 38, then +2 = 40.”
• Counting on from the bigger number: For 57 + 5, “Start at 57. Count on 5: 58, 59, 60, 61, 62. So total is 62.”
• Using doubles (nearby doubles): For 28 + 4, “4 is double 2, but we can also do 28 + 2 + 2. That gives 30, then 32.” Teacher emphasises: “Use known facts to make adding easier, then write a clear number sentence.”

3. 15–25 min · Guided practice (strategy choice). Teacher shows a set of sums one at a time; students decide the best strategy and solve in books (students may choose a different strategy if they can justify it). Include these examples in order:

• 34 + 6
• 57 + 5
• 28 + 4
• 13 + 7 Teacher listens for correct strategy use:
• For 13 + 7, prompt: “Can you make ten? What is 13 + 7 in ones/tens?” (13 + 7 = 20; use ones to make 10, then add remaining ten). Teacher quickly models if needed: “13 + 7 → make ten from 3 + 7.”

4. 25–40 min · Student work: Strategy stations (small groups). Set up 3 stations with 5 minutes each, rotating when instructed. Students use a recording sheet with columns: “Strategy used / How I did it / Answer”.

• Station A: Make-ten cards. Problems: 91 + 6, 84 + 3, 66 + 4, 80 + 5, 24 + 9. Students aim to identify which ones add to 10 (or close to 10), then use tens adjustment.
• Station B: Doubles and near-doubles. Problems: 30 + 3, 42 + 7, 19 + 10, 18 + 5, 22 + 8. Students look for doubles (e.g., adding 4 as 2 + 2; 8 as 4 + 4; 10 as 5 + 5) and justify steps.
• Station C: Counting-on paths. Problems: 44 + 3, 15 + 5, 28 + 4 (or another review sum), 24 + 9 (if needed), 30 + 3 (if needed). Students practise efficient counting-on (count by 1 for a few steps or group steps when numbers allow). Teacher circulates, asks: “Which known fact did you use?” “How did you know your answer is reasonable?” and checks written working.

5. 40–52 min · Whole-class share: compare strategies. Teacher selects 3 student examples (one strong make-ten, one doubles, one counting-on). Students explain using sentence starters:

• “I chose making ten because…”
• “I used a known fact like… so I did…”
• “My answer makes sense because…” Teacher reinforces that different strategies can reach the same correct total, but explanations should be clear.

6. 52–58 min · Independent check (quick quiz). Students complete 6 problems silently, using any strategy but showing at least one step or representation:

• 13 + 7
• 91 + 6
• 84 + 3
• 18 + 5
• 22 + 8
• 44 + 3 Teacher collects and marks for strategy accuracy and reasoning.

7. 58–60 min · Exit ticket (2 questions).

• Q1: “Which strategy helped you most today? (making ten / doubles / counting on)”
• Q2: “Write one sentence explaining how you solved one sum: __ + __ = __ because…”

Resources

• Recording sheet with strategy columns (Strategy / Steps / Answer)
• Station cards for each set of sums (listed above)
• Number lines 0–100 (class copies or laminated)
• Base ten blocks (optional) and place value mats (tens/ones)
• Doubles/Make-ten reference strips (e.g., 5 + 5, 10 + 10, 9 + 1, 8 + 2 prompts)
• Whiteboards or scrap paper for fast working

Assessment

• Formative during stations: teacher observation of strategy choice, correct counting, and clear working.
• Targeted questioning: “What known fact did you use?” and “How do you know your total is right?”
• Exit ticket review: ability to explain strategy and reasoning in a short sentence.
• Quiz check: accuracy of answers plus evidence of strategy.

Differentiation

• Support: sentence starters for explanations; provide a number line or tens/ones mat; allow using base ten blocks for one station problem before moving to paper-only.
• Support for language: word bank for reasoning (make ten, count on, double, tens, ones, more, total).
• Extension: ask students to solve one problem using a second strategy and compare efficiency (e.g., solve 91 + 6 once by make-ten, then again by counting on).
• SEN/EAL considerations: encourage drawing a quick diagram (circles for tens/ones, or jumps on a number line) alongside the written method; pair students strategically for station talk.