Math lesson plan · 7th grade (Year 8 in England) · 30 minutes
Sale prices and discounts
Decimals and percentages
CCSS 7.RP.A.3England: KS3 NumberEngland: GCSE Foundation Ratio
Objective and success criteria
Students will: Sale prices and discounts.
- I can answer questions on today's skill on my own, without help.
- I can explain each step and say why it works.
- I can check my answer and spot a mistake.
Before and after
Needs first: Decrease an amount by a percentage
Leads to: the next skill in this area.
Materials: Place value chart with tenths and hundredths, Hundred squares, Number lines, Mini whiteboards and pens, Printed student sheet (below).
Warm-up · 4 min
- Quick retrieval from earlier learning (Decrease an amount by a percentage). Students answer on mini whiteboards.
- Show answers together and note who needs support in the main task.
- Decrease 100 by 25%. → 75Prompt: Find 25% of 100.
- A household used 2300 kWh of electricity last year. This year it cut its use by 6%. How many kWh did it use this year? → 2162Prompt: After a 6% decrease, 94% is left.
- Nia says that to decrease 150 by 40% you multiply by 0.4. Find the correct result of decreasing 150 by 40%. → 90Prompt: Multiplying by 0.4 finds the 40% you take away, not what is left.
Hook · 3 min
- Show two prices or race times with decimals and ask which is bigger, then why.
- Share the objective: Sale prices and discounts. Read the success criteria together.
I do: model it · 7 min
- Work through the example out loud, saying why you do each step, not just what you do.
- Example: A pair of trainers costs $20. It is 10% off. What is the sale price? (Type the number only.)
- Step 1: 20 × 0.9 = 18
- Answer: 18
- Pause after each step and ask a student to say what comes next.
We do: guided practice · 6 min
- Do these together. Students try each step on whiteboards before you reveal it.
- Use the hints as prompts rather than giving the answer.
- A pair of trainers costs $72. It is 40% off. What is the sale price? (Type the number only.) → 43.2Prompt: Find 40% of the price.
- A jacket was $70 and is now $59.50. What percentage discount is that? → 15Prompt: Find the amount taken off.
You do: independent practice · 7 min
- Students work on the student sheet. Circulate and check the first two answers of every student early.
- Students who finish: write a question of their own for a partner, with the answer.
The 6 questions are on the student sheet below, with answers in the key.
Exit ticket · 3 min
- Two questions on their own. Sort answers into got it / nearly / not yet to plan the next lesson.
- A shop takes 40% off a $430 bike, then an extra 10% off the sale price. What is the total percentage discount? (It is not 50%.) → 46Prompt: Work out the final price step by step.
- A jacket was $56 and is now $28. What percentage discount is that? → 50Prompt: Find the amount taken off.
Watch out for
- Thinking 0.45 is bigger than 0.5 because 45 is bigger than 5.
- Moving the digits the wrong way when multiplying or dividing by 10.
Support and stretch
Support
- Review first: Decrease an amount by a percentage.
- Use concrete materials: place value chart with tenths and hundredths.
- Give the first step of each question, or a partly worked example to finish.
- Pair with a confident partner for the guided practice.
Stretch
- Explain a common mistake in writing and how to fix it.
- Write a word problem that uses today's skill, then solve a partner's.
Homework and more practice
Free online practice with hints and printable worksheets for this skill: eurekami.com/math/grade-7.
Free lesson plan from eurekami.com/lesson-plan-builder