Math lesson plan · 3rd grade (Year 4 in England) · 45 minutes
Break apart a multiplication (distributive property)
Multiplication and division
CCSS 3.OA.B.5CCSS 3.MD.C.7.CEngland: Y4 Multiplication and division
Objective and success criteria
Students will: Break apart a multiplication (distributive property).
- 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: Write a multiplication sentence for an array; Times tables: 2, 5 and 10
Leads to: Multiply a two-digit number by a one-digit number by partitioning; Multiply two-digit numbers with an area model
Materials: Counters for arrays, Multiplication grid, Base-ten blocks, Mini whiteboards and pens, Printed student sheet (below).
Warm-up · 5 min
- Quick retrieval from earlier learning (Write a multiplication sentence for an array; Times tables: 2, 5 and 10). Students answer on mini whiteboards.
- Show answers together and note who needs support in the main task.
- 5 × 4 = ? → 20Prompt: Count in 5s, 4 times.
- 10 × 9 = ? → 90Prompt: Count in 10s, 9 times.
- 12 × 5 = ? → 60Prompt: Count in 5s, 12 times.
Hook · 5 min
- Show an array of chairs, eggs or windows and ask how many there are without counting one by one.
- Share the objective: Break apart a multiplication (distributive property). 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: Work out 4 × 35 by splitting 35 into 30 + 5.
- Step 1: 4 × 30 = 120
- Step 2: 4 × 5 = 20
- Step 3: 120 + 20 = 140
- Answer: 140
- 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.
- Work out 6 × 29 by splitting 29 into 20 + 9. → 174Prompt: What is 6 × 20?
- Work out 8 × 11 by splitting 11 into 10 + 1. → 88Prompt: What is 8 × 10?
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.
- Work out 7 × 27 by splitting 27 into 20 + 7. → 189Prompt: What is 7 × 20?
- Work out 4 × 45 by splitting 45 into 40 + 5. → 180Prompt: What is 4 × 40?
Watch out for
- Thinking multiplying always makes a number bigger.
- Dropping a zero in long multiplication when moving to the tens row.
Support and stretch
Support
- Review first: Write a multiplication sentence for an array.
- Use concrete materials: counters for arrays.
- 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: Multiply a two-digit number by a one-digit number by partitioning; Multiply two-digit numbers with an area model.
- 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-3.
Free lesson plan from eurekami.com/lesson-plan-builder