Year 5

# Using factors to multiply

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## Lesson details

### Key learning points

- In this lesson, we will begin by introducing the context of synchronized swimmers arranged in groups within squads to multiply three numbers in different arrangements. They use different factor pairs to solve the same problem in different ways. We will also look at distributive law can be represented using area models.

### Licence

This content is made available by Oak National Academy Limited and its partners and licensed under Oak’s terms & conditions (Collection 1), except where otherwise stated.

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### 5 Questions

Q1.

What calculation is represented by the dienes shown below?

20 x 21

203 x 23

25 x 25

Q2.

What four products are missing from the area model shown?

12, 70, 12, 4

21, 70, 40, 12

7, 12, 120, 400

Q3.

What calculations do the dienes represent below?

10 x 47

40 x 6

6 x 11

Q4.

Using your knowledge of multiplying with multiples of ten, can you identify the correct answer for 29 x 21?

580

600

629

Q5.

Look at the calculation carefully. There is an error but the pupils can't decide where! Which pupil is right?

Abdul thinks the person has multiplied by 3 incorrectly.

Lucy believes the regrouping has been incorrect on two occasions.

Safin believes the columns have been added incorrectly so the total is wrong.

### 5 Questions

Q1.

Which of the following statements about a prime number is true?

A prime number multiplied by a prime number will give a product that is a prime number

All prime numbers are odd.

The largest prime number is 97

Q2.

Using distributive law, which of the following number statements is FALSE?

10 X 6 = 5 X 6 + 5 X 6

22 X 2 = 20 X 2 + 2 X 2

3 X 6 = 3 X 3 + 3 X 3

Q3.

Look at the bar model below which is similar to other bar models used during the lesson. Which number statement does the bar model correctly represent to help us calculate the total number of swimmers?

12 x 4 x 3

3 x 3 x 4

4 x 2 x 2

Q4.

Below is an area model. What is the product of this area model?

15

30

9

Q5.

During the lesson, we demonstrated how an area model could be arranged to show distributive law after one of the factors was partitioned. If the product for a calculation is 120, what are the two missing values?

1 and 9

6 and 6

9 and 0