Free Grade 3 Substitution Flashcards
Free Grade 3 flashcards for Substitution: 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
25 min
24
Learning objectives
Every objective is checkable, and each one maps to an activity and an assessment.
- UnderstandExplain substitution
Explain substitution accurately in a familiar context.
Assessed by: Exit ticket of four short items
- ApplyCalculate substitution
Calculate substitution accurately in a familiar context.
Assessed by: Exit ticket of four short items
- AnalyseCompare substitution
Compare substitution accurately in a familiar context.
Assessed by: Exit ticket of four short items
- EvaluateJustify substitution
Justify substitution 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 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 + 11 when x = 4.[1]
- 2.Find the value of 7x + 9 when x = 9.[1]
- 3.Find the value of 6x + 13 when x = 3.[1]
- 4.Find the value of 2x + 3 when x = 7.[1]
- 5.Simplify 8x + 2y + 9x − 1y.[2]
- 6.Simplify 6x + 6y + 5x − 8y.[2]
- 7.Simplify 4x + 4y + 4x − 9y.[2]
- 8.Simplify 5x + 8y + 5x − 9y.[2]
- 9.Expand 3(3x + 9).[3]
- 10.Expand 3(3x + 1).[3]
- 11.Expand 4(5x + 1).[3]
- 12.Expand 4(4x + 7).[3]
Show answers and working
1. 31
Replace x with 4: 5 × 4 + 11. 20 + 11 = 31.
2. 72
Replace x with 9: 7 × 9 + 9. 63 + 9 = 72.
3. 31
Replace x with 3: 6 × 3 + 13. 18 + 13 = 31.
4. 17
Replace x with 7: 2 × 7 + 3. 14 + 3 = 17.
5. 17x + 1y
Collect x terms: 8x + 9x = 17x. Collect y terms: 2y − 1y = 1y.
6. 11x − 2y
Collect x terms: 6x + 5x = 11x. Collect y terms: 6y − 8y = -2y.
7. 8x − 5y
Collect x terms: 4x + 4x = 8x. Collect y terms: 4y − 9y = -5y.
8. 10x − 1y
Collect x terms: 5x + 5x = 10x. Collect y terms: 8y − 9y = -1y.
9. 9x + 27
Multiply each term inside by 3. 3 × 3x = 9x, 3 × 9 = 27.
10. 9x + 3
Multiply each term inside by 3. 3 × 3x = 9x, 3 × 1 = 3.
11. 20x + 4
Multiply each term inside by 4. 4 × 5x = 20x, 4 × 1 = 4.
12. 16x + 28
Multiply each term inside by 4. 4 × 4x = 16x, 4 × 7 = 28.
Worked examples
Find the value of 9x + 12 when x = 4.
- Replace x with 4: 9 × 4 + 12.
- 36 + 12 = 48.
- Answer: 48
Simplify 7x + 2y + 5x − 9y.
- Collect x terms: 7x + 5x = 12x.
- Collect y terms: 2y − 9y = -7y.
- Answer: 12x − 7y
Expand 3(4x + 3).
- Multiply each term inside by 3.
- 3 × 4x = 12x, 3 × 3 = 9.
- Answer: 12x + 9
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
How mastery is evidenced, and which standards it maps to.
Every free resource for Substitution
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Frequently asked
- Is this Grade 3 Substitution flashcards really free?
- Yes. Every flashcards 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 Collecting Like Terms, Using Letters for Numbers, Number Sense. Each one has its own free lesson, worksheet and quiz.
- How is the flashcards 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?
- Move on to Expanding Brackets, Factorising, Algebraic Fractions, Equations, which build directly on this idea.
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