Math lesson plan · 3rd grade (Year 4 in England) · 45 minutes
Find the unknown in multiplication and division equations
Multiplication and division
CCSS 3.OA.A.4England: Y3 Multiplication and division
Objective and success criteria
Students will: Find the unknown in multiplication and division equations.
- 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: Multiplication and division fact families
Leads to: Solve equations with a letter for the unknown
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 (Multiplication and division fact families). Students answer on mini whiteboards.
- Show answers together and note who needs support in the main task.
- Which fact belongs in the same family as 10 × 10 = 100? (10 + 10 = 20 / 100 ÷ 11 = 10 / 100 − 10 = 90 / 100 ÷ 10 = 10) → 100 ÷ 10 = 10Prompt: A fact family uses the same three numbers: 10, 10 and 100.
- Given 3 × 3 = 9, what is 9 ÷ 3? → 3Prompt: Division undoes multiplication.
- Which fact belongs in the same family as 10 × 2 = 20? (20 ÷ 11 = 2 / 10 + 2 = 12 / 20 ÷ 10 = 2 / 20 − 10 = 10) → 20 ÷ 10 = 2Prompt: A fact family uses the same three numbers: 10, 2 and 20.
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: Find the unknown in multiplication and division equations. 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: What number does ▢ stand for? 30 = ▢ × 10
- Step 1: 30 = 3 × 10
- Step 2: 3
- Answer: 3
- 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.
- What number does ▢ stand for? 3 × ▢ = 21 → 7Prompt: Read the equation as a sentence: what times or divided by what?
- Jamal thinks of a number and multiplies it by 7. The answer is 35. What was the number? → 5Prompt: Write it as ▢ × 7 = 35.
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.
- Mei thinks of a number and multiplies it by 4. The answer is 20. What was the number? → 5Prompt: Write it as ▢ × 4 = 20.
- What number does ▢ stand for? 2 × ▢ = 14 → 7Prompt: Read the equation as a sentence: what times or divided by what?
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: Multiplication and division fact families.
- 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: Solve equations with a letter for the unknown.
- 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