Unit Context

Unit: Mastering Place Value (Lesson 7 of 10)
Grade: 6
Duration: 60 minutes
Class size: 30 students
Curriculum Alignment: Alberta Mathematics Program of Studies (Grade 6, Number, Patterns, and Relations)

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Alberta Curriculum References

• Number: Number Concepts (6-4)
  Use place value understanding to read, write, compare, order, and compute with decimals to thousandths.
• Number: Computation and Estimation (6-5)
  Add and subtract decimals to thousandths, including solving problems arising from real-life contexts.
• Mathematical Processes
  Reasoning and analysing, understanding and solving, communicating, connecting, representing.

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Learning Outcomes (I Can Statements)

By the end of this lesson, students will be able to:

• I can align decimal numbers correctly according to place value when adding and subtracting decimals.
• I can solve addition and subtraction problems involving decimals linked to money and measurement contexts.
• I can check my answers using estimation and reasonableness strategies.

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Success Criteria

Students will demonstrate success when they:

• Correctly place decimals in columns (tenths, hundredths, thousandths) before performing operations.
• Solve at least 4 out of 5 decimal addition and subtraction problems correctly, including word problems.
• Explain how place value affects their calculations and justify their estimation strategy.

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Materials Needed

• Whiteboard and markers
• Decimal place value charts (large and individual mini-charts)
• Base-ten blocks or decimal grids (optional, for tactile learners)
• Worksheets with decimal addition/subtraction problems (including money/measurement contexts)
• Calculators (for checking work only)
• Dyslexia-friendly instruction sheets (large font, clear spacing, coloured overlays optional)
• Sticky notes or index cards for exit slips

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Lesson Breakdown

1. Introduction and Review (10 minutes)

• Activate prior knowledge: Briefly review place value with decimals, using place value charts showing tenths, hundredths, and thousandths.
• Ask: "What happens when we add or subtract whole numbers? How do decimals fit in the place value chart?"
• Use a visual aid to show aligning decimals in a vertical format.
• Review how decimals relate to money (dollars and cents) and measurements (e.g., kilograms, litres, metres).

Differentiation:

• Provide a dyslexia-friendly handout summarising place value concepts with visuals and colour coding.
• Use tactile decimal grids or base-ten blocks to support concrete understanding.

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2. Explicit Teaching: Aligning and Calculating Decimals (15 minutes)

• Demonstrate step-by-step adding decimals on the board, aligning by the decimal point.
• Highlight the importance of placing zeroes as placeholders if necessary.
• Repeat demonstration with subtraction.
• Emphasise checking place value positions throughout.

Example:

• Add 3.76 + 1.428
• Subtract 7.805 − 2.69

Class interaction:

• Ask volunteers to replicate the process on the board.
• Address misconceptions (e.g., not aligning decimals, ignoring zeros).

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3. Guided Practice (15 minutes)

• Distribute decimal addition and subtraction problems involving real-life contexts.
• Tasks include:
  • Adding prices with sales tax (Money context)
  • Subtracting lengths of materials (Measurement context)
• Students work in pairs to encourage discussion and peer support; teacher circulates to offer targeted help.

Differentiation:

• Provide scaffolded problems for students needing extra support: fewer decimal places or fill-in-the-blank steps.
• Challenge advanced learners with multi-step or word problems requiring critical thinking and reasoning.

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4. Independent Practice and Self-Assessment (10 minutes)

• Students choose two problems from a worksheet to solve independently.
• They will estimate answers before calculating to check for reasonableness.
• Encourage students to use at least one strategy to verify their answer (e.g., rounding decimals before adding or subtracting).

Extension:

• Identify and solve a "challenge question" requiring addition and subtraction in multi-step problems (e.g., calculating total cost after discounts and tax).

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5. Wrap-up and Reflection (10 minutes)

• Exit slip: Write one “I can…” statement reflecting today’s learning and one question they still have.
• Discuss as a class:
  • Why is aligning decimals important?
  • How does understanding place value help us in everyday life?
• Highlight the importance of accuracy in money and measurement calculations.

Dyslexia-friendly options: Oral sharing can be used instead of writing for students who prefer verbal expression. Visuals will be displayed during discussion.

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Differentiation Strategies

Learner Group	Strategies
Students with dyslexia	Use dyslexia-friendly fonts and high-contrast colours in materials; allow oral responses; break steps down clearly.
Students needing extra support	Use concrete manipulatives; provide partially completed problems; offer one-on-one or small group help.
Advanced learners	Multi-step, real-world reasoning problems; create their own addition/subtraction decimal problems to share.
English Language Learners	Use visuals, vocabulary posters (e.g., decimal, tenths, hundredths); partner work for peer scaffolding.

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Assessment Plan

• Formative Assessment:

  • Observation during guided practice and independent work.
  • Exit slips to check understanding and misconceptions.

• Summative (informal):

  • Accuracy of completed problems in classwork (minimum 80% correct).
  • Ability to explain reasoning and use estimation techniques.

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Teacher Reflection Notes

• Monitor if students confuse place value columns when aligning decimals and intervene early.
• Check engagement level during pair work—consider mixed-ability pairs for peer learning.
• Plan to revisit estimation strategies in future lessons for reinforcement.

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Summary

This lesson supports Alberta’s curriculum aims by deepening students’ decimal computation skills grounded in place value. The focus on real-world money and measurement contexts prepares students for practical application, while differentiation and dyslexia-friendly approaches ensure inclusiveness and accessibility. The combination of visual aids, hands-on practice, discussion, and reflective assessment is designed to engage and empower all learners.