Mathematics

Intermediate

50 mins

Teacher/Student led

Learning Goals

Learning Outcomes

Lesson Files

+80 XP

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Multiplying a Two-digit Number by One Digit: Partition First

Learn to multiply two-digit numbers by one digit using partition. Split the number into tens and units, multiply each part, then add the results together.

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1 Getting Started
2 Watch and Notice
3 Try It Together
4 Work It in Your Copy
5 Class Challenge
6 What Did We Notice?
7 What's Next
Pupil practice

1 - Getting Started ~3 mins

Key point

Illustration for Getting Started Splitting a number up like that has a maths name — we call it partitioning.

Roughly how much is 23 × 3? Guess in your head first, then a few of you will share your guess. Now here is the clever bit: what if we broke twenty-three into twenty and three to make it easier?

👇 Mark your steps as done as you complete them.

+5 XP

2 - Watch and Notice ~8 mins

Each rectangle splits the two-digit number into a tens part and a units part. Watch how each part gets its own area, and how the two areas add up to the whole answer.

👇 Mark your steps as done as you complete them.

+10 XP

3 - Try It Together ~8 mins

Key point

Now let's build one together. One pupil comes to the board and sets 15 × 2 on the area model, and the rest of us watch and agree the two part-areas out loud before anyone adds. We split fifteen into its tens part and its units part, find the area of each part, and add the two areas to reach the total. After this one we build 22 × 3 and 24 × 4 the same way, one at a time on the same model.

Split, multiply each part, add

+15 XP

4 - Work It in Your Copy ~3 mins

COPYBOOK MOMENT

In your maths copy, work 24 × 3 and 15 × 3 by partitioning. For each one, write the tens product on one line and the units product on the next line, then add them to find the total.

+10 XP

5 - Class Challenge ~7 mins

Key point

Today we build and read the area for these, in order: 13 × 2, then 21 × 4, then 17 × 3, then 26 × 3. Each one splits into a tens part and a units part, and for 17 × 3 and 26 × 3 the units part is bigger than ten — so say each part-area aloud before we add.

Partition and multiply

+15 XP

Pupil practice

Module 2 · The Four Operations: Mental and Written Number

Lesson 24 · Multiplying a Two-digit Number by One Digit: Partition First

Download Activity Book page (PDF)

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Multiplying a Two-digit Number by One Digit: Partition First

Teacher Class Feed

1 - Getting Started ~3 mins

2 - Watch and Notice ~8 mins

3 - Try It Together ~8 mins

Split, multiply each part, add

4 - Work It in Your Copy ~3 mins

5 - Class Challenge ~7 mins

Partition and multiply

Unlock the full learning experience

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