Significant figures

Significant figures

Pencil and paper
Overview
Using this Resource
Connecting to the Curriculum
Marking Student Responses
Working with Students
Further Resources
This task is about significant figures.
Write down the number of significant figures in each of the following numbers.

young man with an electric guitar

 

a)
A musician ...
 
 
i)
 
ii)
 
iii)
sells 125,465 albums.   __________ significant figures
 
performs to 36,028 fans.   __________ significant figures
 
makes $3,200,000 in a year.   __________ significant figures
vintage cellphone
b)
A cell phone company charged ...
 
 
i)
 
ii)
 
iii)
$19.95 for a call to Hong Kong.   __________ significant figures
 
$120.05 for a new phone.   __________ significant figures
 
$0.105 per minute for an off-peak call.   __________ significant figures
Task administration: 
This task is completed with pencil and paper only.
Level:
5
Curriculum info: 
Maths, Number and Algebra, Number Knowledge
Keywords: 
significant figures
Description of task: 
Students identify and record the number of significant numbers in both whole numbers and decimal numbers in a range of contexts.
Answers/responses: 
 

Y10 (11/1999)

a)

i)
ii)
iii)

6
5
2

moderate
difficult
difficult

b)

i)
ii)
iii)

4
5
3

difficult
difficult
difficult
 
NOTE: If a) i) and b) i) are the only ones correct, the student probably does not understand significant figures.
Diagnostic and formative information: 
 

Common error

Likely reason

a)   i)
      ii)
      iii)

3
2
4 (or 1)

Number of digits in thousands (and/or millions).

a)   iii)

7

Number of digits. NOTE: a) i) + a) ii) may be coincidentally correct.

a)   ii)
b)   ii)
      iii)

4
3
2

Number of non-zero digits. NOTE: a) i), a) iii) and b) i) may be coincidentally correct.
b)   i)
      ii)
      iii)

2
3
0 or 1

Number of digits before the decimal point.