New
New
Year 5

# Multiply a 2-digit number by a 1-digit number using partitioning and representations (one regroup)

I can use an array to represent multiplication and use place value in an array to represent multiplication of a 2-digit number

New
New
Year 5

# Multiply a 2-digit number by a 1-digit number using partitioning and representations (one regroup)

I can use an array to represent multiplication and use place value in an array to represent multiplication of a 2-digit number

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## Lesson details

### Key learning points

1. Partitioning allows us to multiply the tens and then the ones and recombine the products.
2. The grid can represent the array.
3. Multiply the ones and tens separately and recombine.

### Common misconception

Pupils may not regroup correctly if they do not understand the place value of digits in a factor.

Encourage pupils to use the stem sentences / array to identify when they may need to regroup.

### Keywords

• Array - An array is the layout of items (such as objects, numbers, etc.) arranged in rows and/or columns.

• Product - The result of two or more values multiplied together.

• Regroup - The process of unitising and exchanging between place values is known as regrouping.

Using base ten blocks to represent a multiplication equation initially is useful and all pupils should have access to this representation.
Teacher tip

### Licence

This content is © Oak National Academy Limited (2024), licensed on Open Government Licence version 3.0 except where otherwise stated. See Oak's terms & conditions (Collection 2).

## Starter quiz

### 6 Questions

Q1.
The number 17 can be partitioned into 1 ten and ones.
Q2.
The number 59 can be partitioned into tens and 9 ones.
Q3.
The answer when two or more values are multiplied together is called a .
factor
sum
Q4.
Look at the image. What is the name given to the numbers shown by the arrows?
products
sum
Q5.
Select the array which shows 3 x 4
Pic 1
Pic 3
Q6.
Look at the array. What does it represent?
7 x 3
3 x 7
3 x 9

## Exit quiz

### 6 Questions

Q1.
Which array shows 3 × 18?
pic 2
pic 3
pic 4
Q2.
Which grid represents the multiplication fact 25 × 4?
pic 1
pic 3
Q3.
Which multiplication is represented by this grid model?
23 × 7
207 × 3
7 × 203
Q4.
Match the question with the amount of regrouping.

no regrouping

Correct Answer:23 × 4,regrouping in ones

regrouping in ones

Correct Answer:63 × 2,regrouping in tens

regrouping in tens

Q5.
Select the correct multiplication equation for the following word problem: Lucas is preparing party packs. He has 8 packets of 32 pens. How many pens does he have altogether?
32 + 8