Math lesson plan · 3rd grade (Year 4 in England) · 45 minutes
Multiply a two-digit number by a one-digit number by partitioning
Multiplication and division
CCSS 3.NBT.A.3CCSS 4.NBT.B.5England: Y3 Multiplication and divisionEngland: Y4 Multiplication and division
Objective and success criteria
Students will: Multiply a two-digit number by a one-digit number by partitioning.
- 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: Break apart a multiplication (distributive property); Multiply by multiples of 10
Leads to: Multiply a three-digit number by a one-digit number
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 (Break apart a multiplication (distributive property); Multiply by multiples of 10). Students answer on mini whiteboards.
- Show answers together and note who needs support in the main task.
- 9 × 80 = ? → 720Prompt: 80 is 8 tens.
- 7 × 30 = ? → 210Prompt: 30 is 3 tens.
- 6 × 80 = ? → 480Prompt: 80 is 8 tens.
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: Multiply a two-digit number by a one-digit number by partitioning. 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: 22 × 5 = ?
- Step 1: 20 × 5 = 100
- Step 2: 2 × 5 = 10
- Step 3: 100 + 10 = 110
- Answer: 110
- 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.
- 35 × 4 = ? → 140Prompt: Split 35 into tens and ones: 30 + 5.
- There are 3 vases with 17 flowers in each. How many flowers are there altogether? → 51Prompt: You need 3 × 17.
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.
- Arjun worked out 18 × 6 as 10 × 6 + 8 = 68. What mistake was made, and what is the right answer? → 108Prompt: Did Arjun multiply both parts of 18 by 6?
- 28 × 2 = ? → 56Prompt: Split 28 into tens and ones: 20 + 8.
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: Break apart a multiplication (distributive property).
- 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 three-digit number by a one-digit number.
- 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