New
New
Year 5

# Use knowledge of column addition and subtraction to calculate with decimals: tenths and hundredths

I can use knowledge of column addition and subtraction to calculate with decimals with tenths and hundredths.

New
New
Year 5

# Use knowledge of column addition and subtraction to calculate with decimals: tenths and hundredths

I can use knowledge of column addition and subtraction to calculate with decimals with tenths and hundredths.

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## Lesson details

### Key learning points

1. Numbers are recorded in columns with the same value digits in each column
2. Identify if regrouping will occur
3. If the value of a digit in the minuend is greater than the same digit in the subtrahend, you will need to regroup
4. Make sure that any regrouped numbers are added in with others of the same value

### Common misconception

Where regroupings are required, pupils may not be concise in their jottings.

Encourage pupils to articulate what each number represents in each calculation, demonstrating the calculations with place value counters.

### Keywords

• Hundredth - The name we give to one part of one hundred equal parts.

• Tenth - The name we give to one part of ten equal parts.

• Regroup / regrouping - The process of unitising and exchanging between place values.

Whilst some of the numbers used could be tackled mentally, they have been used to help scaffold thinking as pupils develop their understanding for column methods using decimals. Encourage pupils to reason using place value counters.
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.
Tick all the expressions that would make or bridge 10.
5 + 4
8 + 1
Q2.
Order the expressions from the smallest amount to the largest amount.
1 - 6 + 7
2 - 2 + 9
3 - 14 – 5
4 - 5 + 3
5 - 12 − 6
Q3.
Q4.
Complete the column subtraction and write in the answer.
Q5.
Tick the calculations that require a regrouping.
6.7 – 4.2
Q6.
Tick the correct explanation of the mistake that has been made.
Correct answer: The number of ones that have been regrouped is incorrect.
They did not need to regroup.
The decimal points are not lined up correctly.

## Exit quiz

### 6 Questions

Q1.
Q2.
Complete the column subtraction and write in the answer.
Q3.
How many regroupings does this calculation require?
1 regrouping