New
New
Year 1

# Solve addition and subtraction problems involving length

I can solve addition and subtraction problems involving length.

New
New
Year 1

# Solve addition and subtraction problems involving length

I can solve addition and subtraction problems involving length.

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## Lesson details

### Key learning points

1. Addition and subtraction problems both involve a whole and its parts.
2. You can think about addition and subtraction stories involving length and identify the whole and its parts.
3. When you join two items together, you can add their lengths together to find the total length.
4. When you remove part of an object, you subtract the amount you have removed to find the length of the remaining part.

### Common misconception

Children may confuse standard and non-standard units, for example measuring the height of a tower by counting the blocks rather than using a ruler to measure its length in centimetres.

Use prompts such as, 'How many centimetres tall is this tower?' and, 'The first part of the tower is 10cm tall.' to reinforce the use of centimetres as a standard unit of measure.

### Keywords

• Part - A piece or section of the whole.

• Whole - All of something. Complete.

Look for meaningful contexts within the classroom environment to explore further addition and subtraction problems involving length, for example cutting pieces of wool or string in DT lessons, or when growing plants in science.
Teacher tip

### Licence

This content is Β© 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.
What is the missing part in the part-part-whole model?
Q2.
What is the missing whole in the bar model?
Q3.
Which equation matches this representation of doubling?
5 + 5 = 10
Correct answer: 6 + 6 = 12
2 + 2 = 4
Q4.
19 is equal to plus 10
Q5.
Match the doubling representations to their equations.
Correct Answer:π’π’π’π΅π΅π΅,3 + 3 = 6

3 + 3 = 6

Correct Answer:β«β«β«β«β«βͺβͺβͺβͺβͺ,5 + 5 = 10

5 + 5 = 10

Correct Answer:π£π£π£π£π‘π‘π‘π‘,4 + 4 = 8

4 + 4 = 8

Q6.
Which equation does this βfirst, then, nowβ story represent?
8 β 6 = 2
6 β 2 = 8
Correct answer: 8 β 2 = 6
8 β 8 = 6

## Exit quiz

### 6 Questions

Q1.
Look at the tower of blocks. It shows that 6 cm is a part and 10 cm is a part. 16 cm is the .
Q2.
True or false. If we change the order of the addends, the sum stays the same.
False
Q3.
Match the double number to the correct total.

10

12

14

Q4.
Look at the part-part-whole model. Match the numbers to the correct words,

a part

the whole

a part

Q5.
Look at the playdough snake that Lucas made. The whole snake was 16 cm long. He snipped off a part and the part that was left was 6cm long. How long was the part that Lucas snipped off? cm.
Q6.
Which calculations could this part-part-whole model show?
10 cm + 18 cm = 8 cm
Correct answer: 18 cm β 10 cm = 8 cm
Correct answer: 18 cm = 10 cm + 8 cm