Percentage complete

Percentage complete

Pencil and paper
Overview
Using this Resource
Connecting to the Curriculum
Marking Student Responses
Working with Students
Further Resources
This task is about finding percentages and percentages of amounts.

Jenny is printing out pages off her computer. As each page is printed, a box flashes on the computer screen showing what percentage of the document has been completed. For example, when 5 pages of a 10 page document have been printed, the computer will flash:
 


 
a) i) If 4 out of 5 pages of another document have been printed, write the percentage completed that would be shown in the box.
 


 
  ii) If 13 out of 20 pages of another document have been printed, write the percentage completed that would be shown in the box.
 


 
b) i) If a document is 8 pages long, and the box flashes 
      
how many pages have been printed? __________
  
  ii) If a document is 30 pages long, and the box flashes 
      
how many pages have been printed? __________
  
  iii) If a document is 40 pages long, and the box flashes 
      
how many pages have been printed? __________

 

Task administration: 
This task is completed with pencil and paper only.
 
Level:
4
Curriculum info: 
Maths, Number and Algebra, Number Strategies
Keywords: 
percentages
Description of task: 
Students express proportions as percentages and calculate percentages.
Learning Progression Frameworks
This resource can provide evidence of learning associated with
Multiplicative thinking, sets 6-7
within the Mathematics Learning Progressions Frameworks.
Read more about the Learning Progressions Frameworks.
Answers/responses: 
 

Y9 (03/99)
a) i)
ii)		 80
65		 difficult
difficult
b) i)
ii)
iii)		 6
27
18		 difficult
very difficult
very difficult
Diagnostic and formative information: 
  Common error Likely calculation Likely reason
a) i)
    ii)		 40
130		   4 × 10
13 × 10		 Sees percentage as same as multiplying by 10.
a) i)
b) ii)		 90
29		   Sees a fraction where the numerator is one less than the denominator as equivalent to 90%.
a) i)
    ii)		 20
26		   4 × 5
13 × 20		 Wrong concept of percentage or simply multiplying numbers together.
b) i) -
    iii)		 Close to correct answer   Estimating rather than calculating percentages.