Buying some things

Buying some things

Auto-markingPencil and paperOnline interactive
Overview
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Further Resources
This task is about working out change from buying things.

Some friends each saved up $15 and went shopping.

Question

a) Select all the things that costs under $15.

    • 16 dollar CD

    • photo frame

Question

b) Aleisha bought 2 things with her $15.

    She got $5 change.

    Select the 2 things she bought.

    • photo frame

Question

c) Sandra bought 2 things with her $15.

    She got $3 change.

    Select the 2 things she bought.

    • photo frame

Question

d) Geena bought 3 things with her $15.

    Select the 3 things she bought.

    • photo frame

Task administration: 
This task can be completed with pen and paper or online (with auto marking).
Level:
2
Description of task: 
Students addition and subtraction to work out what they can buy with given amounts of money, and the change they will get.
Curriculum Links: 
 
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: 
   
Y4 (11/2013)
a)
Ticks Poster, Teddy bear, Pen and Photo frame and no others
6-fifty-poster.png  8-fifty-teddy.png  5-fifty-photo-frame.png
very easy
b) Ticks Teddy bear and Pen and no others

6-fifty-poster.png    1-fifty-pen.png
easy
c) Ticks Poster and Photo frame and no others

6-fifty-poster.png    5-fifty-photo-frame.png
moderate
d) Ticks Poster, Pen and Photo frame and no others

6-fifty-poster.png  1-fifty-pen.png  5-fifty-photo-frame.png
moderate
Based on an online sample of 37 Year 4 students.
Diagnostic and formative information: 
  Common error Likely reason Next steps
c)
Ticks Teddy bear and Pen
(gives a total of $7.00)
Close reading error
The student misreads question as getting change from $10 rather than $15
Get students to read the question again carefully taking note of all elements of the problem.
d)
Ticks Teddy bear, Pen and Photo frame
(gives a total of $15.50)
Place value error: recombining decimals or whole numbers
Students do not "carry" the $1 from the three lots of $0.50 and gets an answer of $14.50
Get students to work with playmoney coins and notes.
They should recombine two lots of 50 cents into $1.
If they also fail to recombine the ones and tens, use $1 and $10 notes.
Also:
Ask the students to find three items that do cost less than a total of $15.