Free Grade 3 Substitution Method in Context Lesson Plans
Free Grade 3 lesson plans for Substitution Method in Context: 12 real questions with a full answer key and worked solutions. An expression uses letters for numbers. Substitute a value to evaluate it, collect like terms to simplify it, and multiply every term in a bracket to expand it.
Free
Foundation
20 min
24
Learning objectives
Every objective is checkable, and each one maps to an activity and an assessment.
- RememberIdentify substitution method in context
Identify substitution method in context accurately in a familiar context.
Assessed by: Exit ticket of four short items
- UnderstandExplain substitution method in context
Explain substitution method in context accurately in a familiar context.
Assessed by: Exit ticket of four short items
- ApplyCalculate substitution method in context
Calculate substitution method in context accurately in a familiar context.
Assessed by: Exit ticket of four short items
- AnalyseCompare substitution method in context
Compare substitution method in context accurately in a familiar context.
Assessed by: Exit ticket of four short items
Prerequisites
Close these gaps first — each has its own free lesson, worksheet and quiz.
How Substitution Method in Context works
An expression uses letters for numbers. Substitute a value to evaluate it, collect like terms to simplify it, and multiply every term in a bracket to expand it.
12 practice questions
Easy to hard, 24 marks in total. Try them first, then open the answers.
- 1.Find the value of 5x + 19 when x = 7.[1]
- 2.Find the value of 2x + 7 when x = 9.[1]
- 3.Find the value of 3x + 10 when x = 4.[1]
- 4.Find the value of 8x + 7 when x = 9.[1]
- 5.Simplify 5x + 6y + 4x − 8y.[2]
- 6.Simplify 3x + 4y + 9x − 8y.[2]
- 7.Simplify 5x + 6y + 9x − 4y.[2]
- 8.Simplify 7x + 4y + 9x − 3y.[2]
- 9.Expand 3(6x + 4).[3]
- 10.Expand 5(5x + 7).[3]
- 11.Expand 2(2x + 1).[3]
- 12.Expand 4(6x + 5).[3]
Show answers and working
1. 54
Replace x with 7: 5 × 7 + 19. 35 + 19 = 54.
2. 25
Replace x with 9: 2 × 9 + 7. 18 + 7 = 25.
3. 22
Replace x with 4: 3 × 4 + 10. 12 + 10 = 22.
4. 79
Replace x with 9: 8 × 9 + 7. 72 + 7 = 79.
5. 9x − 2y
Collect x terms: 5x + 4x = 9x. Collect y terms: 6y − 8y = -2y.
6. 12x − 4y
Collect x terms: 3x + 9x = 12x. Collect y terms: 4y − 8y = -4y.
7. 14x + 2y
Collect x terms: 5x + 9x = 14x. Collect y terms: 6y − 4y = 2y.
8. 16x + 1y
Collect x terms: 7x + 9x = 16x. Collect y terms: 4y − 3y = 1y.
9. 18x + 12
Multiply each term inside by 3. 3 × 6x = 18x, 3 × 4 = 12.
10. 25x + 35
Multiply each term inside by 5. 5 × 5x = 25x, 5 × 7 = 35.
11. 4x + 2
Multiply each term inside by 2. 2 × 2x = 4x, 2 × 1 = 2.
12. 24x + 20
Multiply each term inside by 4. 4 × 6x = 24x, 4 × 5 = 20.
Worked examples
Find the value of 6x + 14 when x = 2.
- Replace x with 2: 6 × 2 + 14.
- 12 + 14 = 26.
- Answer: 26
Simplify 8x + 3y + 9x − 3y.
- Collect x terms: 8x + 9x = 17x.
- Collect y terms: 3y − 3y = 0y.
- Answer: 17x + 0y
Expand 5(4x + 8).
- Multiply each term inside by 5.
- 5 × 4x = 20x, 5 × 8 = 40.
- Answer: 20x + 40
Interactive practice
Free, no account required — answer on screen or print it.
Common mistakes
What learners typically get wrong, and how to fix it.
Reads 3x as 3 + x, or as 3 with x stuck on.
Correction: 3x means 3 × x.
Only multiplies the first term when expanding.
Correction: Draw arrows from the outside to every inside term.
Teacher tips
- · Use algebra tiles to show collecting like terms.
Parent tips
- · Ask what 'number of pizzas × price' is for different orders.
Real-life applications
- · Formulas for cost: total = 5n + 2 for n items plus delivery.
Assessment objectives
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Frequently asked
- Is this Grade 3 Substitution Method in Context lesson plan really free?
- Yes. Every lesson plans on FreeMathWorksheet is free to use, print and share — no account, no paywall and no watermark.
- What should a learner already know before this?
- Start with Working with Substitution Method, Introducing Substitution Method, Elimination Method. Each one has its own free lesson, worksheet and quiz.
- How is the lesson plan sequenced?
- Recognition first, then understanding, application, reasoning and finally mastery — the same ladder used across every free resource on the platform.
- What comes next after Substitution Method in Context?
- Move on to Elimination Method, Graphical Solutions, which build directly on this idea.
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