Correcting mistakes

Correcting mistakes

Pencil and paperOnline interactive
Overview
Using this Resource
Connecting to the Curriculum
Marking Student Responses
Further Resources
This task is about correcting measurement mistakes.

Three students gave incorrect answers to questions about area and perimeter.

Write down the mistake that each student made.

Question 1Change answer

 

Sophie said, "The perimeter of the book is 30 cm."

What was Sophie's mistake?

Question 1Change answer

 

Mike said, "The perimeter of the table top is 6 m."

What was Mike's mistake?

Question 1Change answer

 

Each square of this pattern is 1 cm2. Tom said, "The area of the pattern is 20 cm2."

What was Tom's mistake?

Task administration: 
This task can be completed with pencil and paper or online.
Levels:
3, 4
Key Competencies: 
Description of task: 
Students identify the error in three statements made about the perimeter and area of given objects.
Curriculum Links: 
This resource can help to identify students' understanding of area and perimeter.
Learning Progression Frameworks
This resource can provide evidence of learning associated with within the Mathematics Learning Progressions Frameworks.
Read more about the Learning Progressions Frameworks.
Answers/responses: 
 

Y6 (09/2000)

a)

Any 1 of:

  • She only worked out half of the perimeter.
  • She added 10 + 20 (instead of adding 20 + 10 + 20 + 10).
  • She added two side lengths (instead of adding the four side lengths).
  • Other sensible explanations.

moderate

b)

  • He worked out the area (instead of the perimeter).
  • He multiplied 3 × 2 (instead of adding 2 + 3 + 2 + 3).
  • He counted the squares (instead of adding the side lengths).
  • Other sensible explanations.

moderate

c)

  • He worked out the perimeter (instead of the area).
  • He added 5 + 10 + 5 + 10 (instead of  multiplying 5 × 10).
  • He added the side lengths (instead of multiplying them or counting the squares).
  • Other sensible explanations.

difficult