Area of three shapes

Area of three shapes

Pencil and paper
Overview
Using this Resource
Connecting to the Curriculum
Marking Student Responses
Working with Students
Further Resources
This task is about working out the area of shapes on a grid.
 
a) 
What is the area of this shape
(A) 12 cm2
(B) 13 cm2
(C) 14 cm2
(D) 15 cm2
(E) None of these. The answer is __________ cm2
 
 
 
b)
What is the area of this shape?
(A) 9 cm2
(B) 10 cm2
(C) 11 cm2
(D) 12 cm2
(E) None of these. The answer is __________ cm2
 
 
 
c)
What is the area of this shape?
(A) 5 cm2
(B) 6 cm2
(C) 7 cm2
(D) 8 cm2
(E) None of these. The answer is __________ cm2
Task administration: 
This task can be completed with pencil and paper only.
Copyright: 
Graphics: copyright NZCER.
Level:
4
Curriculum info: 
Maths, Geometry and Measurement, Measurement
Keywords: 
area, unit squares
Description of task: 
Students calculate the area of three shapes with a grid in the background.
Curriculum Links: 
This resource can help to identify students' understanding of calculating area .
Learning Progression Frameworks
This resource can provide evidence of learning associated with
Measurement sense, sets 6-7
within the Mathematics Learning Progressions Frameworks.
Read more about the Learning Progressions Frameworks.
Answers/responses: 
   

Y10 (12/1997)
a) B moderate
b) C moderate
c) B moderate
Diagnostic and formative information: 
  Common errors Likely reason
a)
b)
c)		 E – 16 (or 17)
E – 15 (or 16)
E – 12 (or 11)		 Confuses area and perimeter.
(Calculates perimeter by measuring side lengths.)
b)
c)		 E – 16
E – 10		 Confuses area and perimeter.
Calculates perimeter by assuming all diagonals have a length of 1 cm.
If a) B is chosen in combination with these two it is likely that the answer to a) is correct for the wrong reasons.