Year 5

Year 5

# Long multiplication

## Lesson details

### Key learning points

1. In this lesson, we will explore area models using Dienes blocks to represent multiplication. This is connected to the steps involved in long multiplication and we will then gain experience with the formal algorithm.

### 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.

## Video

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## Worksheet

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## Starter quiz

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### 5 Questions

Q1.
What calculation is represented by the area model?
10 x 16
12 x 13
6 x 25
Q2.
When trying to estimate 153 x 4, which derived number fact is important to know?
100 x 4 = 400
Correct answer: 15 x 4 = 60
153 x 2 = 306
The nearest hundred is 200
Q3.
When calculating 313 x 4, which estimation would be most efficient?
300 x 5
350 x 4
400 x 4
Q4.
Summer turned to page one of her maths test and saw the question was 2534 x 6. Last week they were taught both mental strategies and formal written methods and is unsure which one to use. Why would the formal written method be better to use for this question?
It is impossible to make mistakes using short multiplication
Mental strategies work better only on rounded numbers
Correct answer: The question requires a lot of regrouping which can make mental strategies less efficient and effective.
You can run out any mistakes you make.
Q5.
Daniel completed his work in class but when it was marked, he found he had got the following question wrong. He is confused as he is sure he is right and the teacher is wrong! But if he has made a mistake, where is it?
Daniel has not made a mistake, the teacher has marked it wrong incorrectly.
In the hundreds column
In the ones column
Correct answer: In the tens column

## Exit quiz

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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
Correct answer: 21, 70, 120, 400
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