Spending at the shop

Spending at the shop

Auto-markingPencil and paperOnline interactive
Overview
Using this Resource
Connecting to the Curriculum
Marking Student Responses
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Further Resources
This task is about working out change from spending.
Dane, Anahera and Jake each had $10 to spend at the shop.

Question

a) Select all the things that cost less than $10.

    • poster of a jet plane

    • CD

    • comic book

    • T0shirt

    • watch

    • pen

Question

 

b) Dane used his $10 to buy a pen for $1.50. 

    What other could things could he still buy?

    • CD

    • watch

Question 1Change answer

 

c) Anahera used her $10 to buy a pen for $1.50 and a poster for $7.50.

    How much money does she have left? $ 

Question

 

d) Jake bought one thing with his $10 and got $3.50 change.

    What did he buy?

    • CD

    • watch

Question

 

e) Jake had his $3.50 change.

    If he had $8.50 more what would he have the exact amount of money for?

    • CD

    • watch

Task administration: 
This task can be completed with pen and paper or online (with auto marking).
Copyright: 

All clipart from clker.com

Level:
2
Curriculum info: 
Maths, Number and Algebra, Number Strategies
Keywords: 
money, addition, subtraction, spending, change
Description of task: 
Students order possible items, work out the change from $10 or the shortfall for different items.
Learning Progression Frameworks
This resource can provide evidence of learning associated with
Additive thinking, set 5
within the Mathematics Learning Progressions Frameworks.
Read more about the Learning Progressions Frameworks.
Answers/responses: 
  Correct response Y4 Oct-Nov 2013
Online
a) Poster, Comic book, Watch and Pen very easy
b)

Poster and Comic Book

One of Poster  and Comic book (none incorrect)

moderate

easy
c) $1 moderate
d) Comic book moderate
e) T-Shirt moderate

Based on a sample of 52 Y4 students

Diagnostic and formative information: 

This resource is about adding and subtracting multiple amounts of money involving 0.5 decimal fractions.
It also looks at amounts greater or less than given amounts. This serves as an indicator about students' understanding about the size of numbers.

The key thing to note is whether students can combine multiple amounts and how they handle adding or subtracting the 0.5 decimal fractions, i.e., whether they carry the "1" correctly. 

Some of the common errors that students can make this resource are:

  Common error Likely reason Next step
b) Does not select one of
Comic book or Poster

 

 Selects one answer rather than looking for all possible answers. Encourage students to work out what the question is asking for: all possible answers when the question appears plural? or one answer only?

c)

Selects Watch ($9.50) as well as Poster and Comic book.

Does not keep the 1.50 subtracted from $10 and then identifies things to buy. 

 Encourage students to work out what the question is asking for. Students could explain as an expression, e.g., $10 - $1.50 = ? and then look for what is less than $8.50

b)

 

c)

 

d)

Selects only Watch ($9.50)

$2

 

Selects Poster ($7.50)

Does not carry the "1" correctly when subtracting the 1.50 from 10.00

Does not carry the "1" correctly when adding 1.50 + 7.50

Does not carry the "1" correctly when subtracting the 3.50 from 10.00

Recombining error

Students need to explore what happens when numbers with parts (decimal fractions) are added and subtracted. Using money and substituting two 50c for $1, and then adding and subtracting amounts should illustrate how recombination works.
c) $9 Correctly recombines the 0.5 decimal fractions, but gives the amounts spent not the the change left.