Calculating Percentages
Solve problems involving the calculation of percentages of amounts (e.g. 15% of 360) and the use of percentages for comparison
Lesson
Set out your lesson
“Calculating Percentages means practising the idea at the table with counters or paper models and one clear check. We will demo once, then your child tries.”
Bring to the table
- 100-square grid or 10×10 paper
- Pencil
Extra for the adult
Worked example. 25 shaded squares out of 100 is 25%.
Optional challenge. For Calculating Percentages, add one harder example after success.
What to notice. Keep one parent note: examples tried; results; support used. This session samples Calculating Percentages, not mastery.
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Teaching approaches
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1 approach
Calculating Percentages means practising the idea at the table with counters or paper models and one clear check. We will demo once, then your child tries.
Materials: 100-square grid or 10×10 paper; Pencil. Adult shades 25 squares and says 25%. Child shades three percent amounts and names each percent. Done: three correct percent names for shaded parts. Stop after the fresh check; keep optional challenge for another day.
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Practice this concept
Start practiceCalculating Percentages practice
Practice key ideas from Calculating Percentages.
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Learning resources
Extra practice links — they do not replace Gakuva’s teaching approach.
Illustrative Mathematics · Practice link — not the full lesson
Shirt Sale
Before you open · source notes
Shirt Sale supports calculating percentages in a price context. Not every compound-interest model.
Free, no sign-in. A teacher solution is on the same page, so use the student view with your child.
Before you openAsk the learner to find a percent of a price and say the sale amount.
Opening this link does not save learning or assess mastery.
Source, access and review notes
Public Illustrative Mathematics task page. The .html address responds HTTP 308 to this URL. An anonymous GET of this URL on 2026-11-12 returned HTTP 200 with no login or payment prompt. Where a teacher solution is present, it is on the same page as the student task; this check did not find a separate locked student view. An adult can use the student view section and should not read a solution aloud. Advertising was not observed in the fetched HTML text; that is not a browser, device, or ad-free guarantee. This is a paper or discussion task, not an automatically marked interactive game. Opening the link does not save practice or assess mastery. Diagrams on the page use missing or filename-only alt text, so they are not an accessible image equivalent. Accessibility still depends on an adult describing the picture.
Illustrative Mathematics. “Shirt Sale.” Licensed CC BY-NC-SA 4.0. External task; Gakuva does not copy, host, embed, or redistribute it.
CC BY-NC-SA 4.0 — link only
Check understanding
- Calculate 15% of 360 by finding 10% and 5% and combining
- Compare two discounts given as percentages of different original prices
- Explain a strategy for finding any percentage of an amount using known percentage facts
“If a jumper originally costs £40 and is 15% off, can your child work out how much the discount is and what the sale price would be?”
Curriculum record
- Type
- Procedural
- Subject
- Mathematics
- Domain
- Ratio & Proportion
- Age range
- Ages 10–13
Standards