Clothing sale

Clothing sale

Pencil and paper
Overview
Using this Resource
Connecting to the Curriculum
Marking Student Responses
Working with Students
Further Resources
This task is about percentages and discounts.
Tui's Fashions are having a clothing sale.
The table below lists the full price of the sale items and the percentage by which each item has been reduced.
 
a)
Complete the final column of the table by writing in the sale price for each item.
 
 
Item Full Price Sale Discount Sale Price
Jacket   
 $360 50%
 
 
i)   $ __________
Scarf   
 $100 30%
 
 
ii)  $ __________
Shirt   
 $80 5%
 
 
iii) $ __________
Shoes
 $200 7.5%
 
 
iv) $ _________
 
b)
 
Someone purchased a dress for $210 after it had been discounted by 30% in the sale. 
 
What was the full price of the dress before it was discounted?   $ __________
Task administration: 
This task is completed with pencil and paper only.
Level:
5
Curriculum info: 
Maths, Number and Algebra, Number Strategies
Keywords: 
percentages, money, discount
Description of task: 
Using discount percentages, students calculate the sale price of clothes from the original price. They also calculate the original price of a discounted item.
Learning Progression Frameworks
This resource can provide evidence of learning associated with
Multiplicative thinking, sets 8-9
within the Mathematics Learning Progressions Frameworks.
Read more about the Learning Progressions Frameworks.
Answers/responses: 

 

Y10 (11/2000)

a)

i)
ii)
iii)
iv)

180
70
76
185

very easy
easy
easy
easy

b)

  

300

very difficult
Diagnostic and formative information: 
 

Common error

Likely calculation

Likely reason

a)  i)
     iii)
     iv)

310
75
192.50

360 - 50
80 - 5
200 - 7.5

Treats 50% as $50
Treats 5% as $5
Treats 7.5% as $7.50
(Gets a) ii) correct coincidentally by treating 30% as $30).

b)

240

210 + 30

  

a)  ii)
     iii)
     iv)

30
4
15

100 × 0.3
80 × 0.05
200 × 0.075

Gives amount of reduction rather than the sale price.
(Gets a) i) correct coincidentally).

b)

273

210 × 1.3

Adds 30% to 210 rather than saying "30% of what equals 210?"