Solve addition and subtraction problems involving length | Maths

Starter quiz

What is the missing part in the part-part-whole model?
- '7' ✓
What is the missing whole in the bar model?
- '14' ✓
Which equation matches this representation of doubling?
- 5 + 5 = 10
- 6 + 6 = 12 ✓
- 2 + 2 = 4
19 is equal to ______ plus 10
- '9' ✓
Match the doubling representations to their equations.
- 🟢🟢🟢🔵🔵🔵
  
  ⇔
  
  3 + 3 = 6 ✓
- ⚫⚫⚫⚫⚫⚪⚪⚪⚪⚪
  
  ⇔
  
  5 + 5 = 10 ✓
- 🟣🟣🟣🟣🟡🟡🟡🟡
  
  ⇔
  
  4 + 4 = 8 ✓
Which equation does this ‘first, then, now’ story represent?
- 8 − 6 = 2
- 6 − 2 = 8
- 8 − 2 = 6 ✓
- 8 − 8 = 6

Exit quiz

Look at the tower of blocks. It shows that 6 cm is a part and 10 cm is a part. 16 cm is the ______.
- 'whole' ✓
True or false. If we change the order of the addends, the sum stays the same.
- True ✓
- False
Match the double number to the correct total.
- double 5
  
  ⇔
  
  10 ✓
- double 6
  
  ⇔
  
  12 ✓
- double 7
  
  ⇔
  
  14 ✓
Look at the part-part-whole model. Match the numbers to the correct words,
- 5 is
  
  ⇔
  
  a part ✓
- 15 is
  
  ⇔
  
  the whole ✓
- 10 is
  
  ⇔
  
  a part ✓
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.
- '10' ✓
Which calculations could this part-part-whole model show?
- 10 cm + 18 cm = 8 cm
- 18 cm − 10 cm = 8 cm ✓
- 18 cm = 10 cm + 8 cm ✓

Worksheet

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Lesson Details

Key learning points

Addition and subtraction problems both involve a whole and its parts.
You can think about addition and subtraction stories involving length and identify the whole and its parts.
When you join two items together, you can add their lengths together to find the total length.
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.