Math lesson plan · 5th grade (Year 6 in England) · 45 minutes
Compare prices to find the better buy
Measurement
CCSS 6.RP.A.3.BEngland: Y6 Ratio and proportion
Objective and success criteria
Students will: Compare prices to find the better buy.
- 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: Divide a decimal by a whole number; Money problems with several steps
Leads to: the next skill in this area.
Materials: Rulers, scales and measuring jugs, Clock faces, Conversion chart, Mini whiteboards and pens, Printed student sheet (below).
Warm-up · 5 min
- Quick retrieval from earlier learning (Divide a decimal by a whole number; Money problems with several steps). Students answer on mini whiteboards.
- Show answers together and note who needs support in the main task.
- 21.6 ÷ 8 = ? → 2.7Prompt: Divide as if it were a whole number.
- Hiro buys 2 notebooks at $5.80 each and a ruler for $1. Hiro pays with $20. How much change does Hiro get? → 7.4Prompt: Find the total cost first.
- 4 friends share a bill of $21.28 equally. How much does each pay? → 5.32Prompt: Work out 21.28 ÷ 4.
Hook · 5 min
- Ask the class to estimate the length of the room or the weight of a bag before measuring it.
- Share the objective: Compare prices to find the better buy. 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: Pack A has 4 yoghurts for $1.72. Pack B has 12 yoghurts for $6. Which pack is better value?
- Step 1: A: $1.72 ÷ 4 = $0.43
- Step 2: B: $6 ÷ 12 = $0.50
- Step 3: Pack A
- Answer: Pack A
- 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.
- Pack A has 5 yoghurts for $1.30. Pack B has 10 yoghurts for $2.90. Which pack is better value? (Pack A / Pack B) → Pack APrompt: Find the price of one yoghurt in each pack.
- 4 pencils cost $0.84. How much do 8 pencils cost at the same price each? → 1.68Prompt: Find the cost of one pencil first.
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.
- Pack A has 5 yoghurts for $2.35. Pack B has 8 yoghurts for $4.40. Which pack is better value? (Pack A / Pack B) → Pack APrompt: Find the price of one yoghurt in each pack.
- 4 pencils cost $1.08. How much do 8 pencils cost at the same price each? → 2.16Prompt: Find the cost of one pencil first.
Watch out for
- Measuring from the end of the ruler instead of zero.
- Converting units the wrong way (multiplying instead of dividing).
Support and stretch
Support
- Review first: Divide a decimal by a whole number.
- Use concrete materials: rulers, scales and measuring jugs.
- 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-5.
Free lesson plan from eurekami.com/lesson-plan-builder