Math lesson plan · 7th grade (Year 8 in England) · 45 minutes
Share in a given ratio
Ratio and proportion
CCSS 6.RP.A.3England: Y6 Ratio and proportionEngland: KS3 RatioEngland: GCSE Foundation RatioEngland: 11+ Ratio
Objective and success criteria
Students will: Share in a given ratio.
- 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: Understand ratios
Leads to: Ratio problems with algebra; Share an amount in a ratio with three parts
Materials: Bar models, Double number lines, Ratio tables, Mini whiteboards and pens, Printed student sheet (below).
Warm-up · 5 min
- Quick retrieval from earlier learning (Understand ratios). Students answer on mini whiteboards.
- Show answers together and note who needs support in the main task.
- Simplify the ratio 24:40. Type it like 3:2. → 3:5Prompt: Find a number that divides both parts.
- 2:5 = 16:__ → 40Prompt: Equivalent ratios are made by multiplying both parts by the same number.
- Simplify the ratio 30:36. Type it like 3:2. → 5:6Prompt: Find a number that divides both parts.
Hook · 5 min
- Share a recipe for 4 people and ask how much is needed for 6.
- Share the objective: Share in a given ratio. Read the success criteria together.
I do: model it · 10 min
- Work through the example out loud, saying why you do each step, not just what you do.
- Example: Ravi and Kai share $77 in the ratio 4:3. How much does Kai get? (Type the number only.)
- Step 1: 4 + 3 = 7
- Step 2: 77 ÷ 7 = 11
- Step 3: 3 × 11 = 33
- Answer: 33
- Pause after each step and ask a student to say what comes next.
We do: guided practice · 10 min
- Do these together. Students try each step on whiteboards before you reveal it.
- Use the hints as prompts rather than giving the answer.
- Omar and Zoe share $56 in the ratio 2:5. How much does Zoe get? (Type the number only.) → 40Prompt: How many parts are there altogether?
- The ratio of adults to children at a show is 3:7. There are 40 more children than adults. How many people are there in total? → 100Prompt: The difference in parts is 4.
You do: independent practice · 10 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 8 questions are on the student sheet below, with answers in the key.
Exit ticket · 5 min
- Two questions on their own. Sort answers into got it / nearly / not yet to plan the next lesson.
- The ratio of adults to children at a show is 3:5. There are 6 more children than adults. How many people are there in total? → 24Prompt: The difference in parts is 2.
- Chloe and Elena share $18 in the ratio 2:1. How much does Elena get? (Type the number only.) → 6Prompt: How many parts are there altogether?
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: Understand ratios.
- 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
- Move on to: Ratio problems with algebra; Share an amount in a ratio with three parts.
- 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