Math lesson plan · 6th grade (Year 7 in England) · 30 minutes
Compare deals to find the better value
Ratio and proportion
CCSS 6.RP.A.3.BEngland: KS3 Ratio, proportion and rates of changeEngland: GCSE Foundation Ratio
Objective and success criteria
Students will: Compare deals to find the better value.
- 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: Work out unit prices
Leads to: the next skill in this area.
Materials: Bar models, Double number lines, Ratio tables, Mini whiteboards and pens, Printed student sheet (below).
Warm-up · 4 min
- Quick retrieval from earlier learning (Work out unit prices). Students answer on mini whiteboards.
- Show answers together and note who needs support in the main task.
- 8 song downloads cost $7.36. What is the price for 1? (Type the number only.) → 0.92Prompt: Unit price = total cost ÷ number of items.
- A 400 g bag of pasta costs $3.36. What is the cost per 100 g? (Type the number only.) → 0.84Prompt: How many lots of 100 g are in 400 g?
- 3 smoothies cost $8.73. At the same price each, how much do 9 smoothies cost? (Type the number only.) → 26.19Prompt: Find the price of one smoothie first.
Hook · 3 min
- Share a recipe for 4 people and ask how much is needed for 6.
- Share the objective: Compare deals to find the better value. 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: Pack A: 6 cans of sparkling water for $4.02. Pack B: 8 cans of sparkling water for $4.96. Which pack is better value?
- Step 1: A: $4.02 ÷ 6 = $0.67
- Step 2: B: $4.96 ÷ 8 = $0.62
- Step 3: Pack B is better value.
- Answer: Pack B
- 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.
- Pack A: 4 cans of sparkling water for $3.56. Pack B: 12 cans of sparkling water for $12.12. Which pack is better value? (Pack A / Pack B) → Pack APrompt: Find the price of ONE item in each pack.
- Phone data plans: Plan A gives 2 GB for $6. Plan B gives 15 GB for $75. Which plan costs less per GB? (Plan A / Plan B) → Plan APrompt: Divide each price by the number of GB.
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.
- Phone data plans: Plan A gives 5 GB for $20. Plan B gives 12 GB for $60. Which plan costs less per GB? (Plan A / Plan B) → Plan APrompt: Divide each price by the number of GB.
- Which bottle of orange juice is the better buy? A: 1000 ml for $1.30. B: 1500 ml for $2.40. (Bottle A / Bottle B) → Bottle APrompt: Compare the price of the same amount, e.g. 100 ml.
Watch out for
- Adding the same amount to both parts instead of multiplying.
- Mixing up part-to-part and part-to-whole ratios.
Support and stretch
Support
- Review first: Work out unit prices.
- Use concrete materials: bar models.
- 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-6.
Free lesson plan from eurekami.com/lesson-plan-builder