Free Grade 3 Introducing Simple Interest Lessons
Free Grade 3 lessons for Introducing Simple Interest: 12 real questions with a full answer key and worked solutions. Per cent means 'out of 100'. Find 10% by dividing by 10 or 1% by dividing by 100, then build up. For an increase or decrease, use a multiplier.
Free
Core
25 min
24
Learning objectives
Every objective is checkable, and each one maps to an activity and an assessment.
- UnderstandExplain introducing simple interest
Explain introducing simple interest accurately in a familiar context.
Assessed by: Exit ticket of four short items
- ApplyCalculate introducing simple interest
Calculate introducing simple interest accurately in a familiar context.
Assessed by: Exit ticket of four short items
- AnalyseCompare introducing simple interest
Compare introducing simple interest accurately in a familiar context.
Assessed by: Exit ticket of four short items
- EvaluateJustify introducing simple interest
Justify introducing simple interest 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 Introducing Simple Interest works
Per cent means 'out of 100'. Find 10% by dividing by 10 or 1% by dividing by 100, then build up. For an increase or decrease, use a multiplier.
12 practice questions
Easy to hard, 24 marks in total. Try them first, then open the answers.
- 1.Find 50% of 520.[1]
- 2.Find 50% of 540.[1]
- 3.Find 50% of 340.[1]
- 4.Find 50% of 560.[1]
- 5.Find 35% of 220.[2]
- 6.Find 40% of 340.[2]
- 7.Find 30% of 60.[2]
- 8.Find 60% of 600.[2]
- 9.Decrease $780.00 by 15%.[3]
- 10.Decrease $400.00 by 12.5%.[3]
- 11.Decrease $420.00 by 5%.[3]
- 12.Increase $240.00 by 20%.[3]
Show answers and working
1. 260
1% of 520 = 5.2. 50% = 5.2 × 50 = 260.
2. 270
1% of 540 = 5.4. 50% = 5.4 × 50 = 270.
3. 170
1% of 340 = 3.4. 50% = 3.4 × 50 = 170.
4. 280
1% of 560 = 5.6. 50% = 5.6 × 50 = 280.
5. 77
1% of 220 = 2.2. 35% = 2.2 × 35 = 77.
6. 136
1% of 340 = 3.4. 40% = 3.4 × 40 = 136.
7. 18
1% of 60 = 0.6. 30% = 0.6 × 30 = 18.
8. 360
1% of 600 = 6. 60% = 6 × 60 = 360.
9. $663.00
Multiplier: 1 − 0.15 = 0.85. 780 × 0.85 = 663.
10. $350.00
Multiplier: 1 − 0.125 = 0.875. 400 × 0.875 = 350.
11. $399.00
Multiplier: 1 − 0.05 = 0.95. 420 × 0.95 = 399.
12. $288.00
Multiplier: 1 + 0.2 = 1.2. 240 × 1.2 = 288.
Worked examples
Find 75% of 580.
- 1% of 580 = 5.8.
- 75% = 5.8 × 75 = 435.
- Answer: 435
Find 5% of 540.
- 1% of 540 = 5.4.
- 5% = 5.4 × 5 = 27.
- Answer: 27
Decrease $620.00 by 20%.
- Multiplier: 1 − 0.2 = 0.8.
- 620 × 0.8 = 496.
- Answer: $496.00
Interactive practice
Free, no account required — answer on screen or print it.
Common mistakes
What learners typically get wrong, and how to fix it.
Finds 10% and stops when asked for a 10% decrease.
Correction: Subtract the 10% from the original.
Thinks a 50% rise then 50% fall returns to the start.
Correction: The second percentage is of a different amount.
Teacher tips
- · Teach 10%, 5%, 1% building blocks before multipliers.
Parent tips
- · Work out the tip at a restaurant together.
Real-life applications
- · Sales, tips, tax and interest.
Assessment objectives
How mastery is evidenced, and which standards it maps to.
Every free resource for Introducing Simple Interest
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Learn — Meet the idea.
Practice — Build fluency.
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Assess — Prove mastery.
Apply — Use it in context.
Teach — Deliver it to a class.
Frequently asked
- Is this Grade 3 Introducing Simple Interest lesson really free?
- Yes. Every lessons 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 Percentage Change. Each one has its own free lesson, worksheet and quiz.
- How is the lesson 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 Introducing Simple Interest?
- Move on to Working with Simple Interest, Simple Interest in Context, Percentage of an Amount, Percentage Increase, which build directly on this idea.
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