Math lesson plan · 5th grade (Year 6 in England) · 45 minutes
Predict the size of a product: multiplying as scaling
Fractions
CCSS 5.NF.B.5.ACCSS 5.NF.B.5.BEngland: Y6 Fractions
Objective and success criteria
Students will: Predict the size of a product: multiplying as scaling.
- 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: Multiply fractions
Leads to: the next skill in this area.
Materials: Fraction strips or a fraction wall, Paper strips to fold, Number lines, Mini whiteboards and pens, Printed student sheet (below).
Warm-up · 5 min
- Quick retrieval from earlier learning (Multiply fractions). Students answer on mini whiteboards.
- Show answers together and note who needs support in the main task.
- Kwame has 45 metres of ribbon and uses 2/5 of it. How many metres is that? → 18Prompt: "Of" means multiply: 2/5 × 45.
- Hana has 18 metres of ribbon and uses 2/3 of it. How many metres is that? → 12Prompt: "Of" means multiply: 2/3 × 18.
- Zoe has 56 metres of ribbon and uses 7/8 of it. How many metres is that? → 49Prompt: "Of" means multiply: 7/8 × 56.
Hook · 5 min
- Cut a pizza or a strip of paper unevenly and ask whether the pieces are really halves or quarters.
- Share the objective: Predict the size of a product: multiplying as scaling. 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: Without calculating: is 89 × 5/3 less than, greater than or equal to 89?
- Step 1: 5/3 > 1
- Step 2: greater than 89
- Answer: greater than 89
- 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.
- Without calculating: is 70 × 3/4 less than, greater than or equal to 70? (less than 70 / greater than 70 / equal to 70) → less than 70Prompt: Is 3/4 less than 1, more than 1, or exactly 1?
- Which product is greatest? 52 × 5/4, 52 × 3/2, 52 × 7/8 (52 × 5/4 / 52 × 3/2 / 52 × 7/8) → 52 × 3/2Prompt: Every product uses 52, so compare the fractions.
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.
- Which product is greatest? 21 × 3/2, 21 × 1/2, 21 × 5/4 (21 × 3/2 / 21 × 1/2 / 21 × 5/4) → 21 × 3/2Prompt: Every product uses 21, so compare the fractions.
- Without calculating: is 81 × 7/4 less than, greater than or equal to 81? (less than 81 / greater than 81 / equal to 81) → greater than 81Prompt: Is 7/4 less than 1, more than 1, or exactly 1?
Watch out for
- Thinking a bigger denominator means a bigger fraction (1/8 > 1/4).
- Adding the denominators when adding fractions (1/2 + 1/3 = 2/5).
Support and stretch
Support
- Review first: Multiply fractions.
- Use concrete materials: fraction strips or a fraction wall.
- 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