What's my number?

What's my number?

Pencil and paper
Overview
Using this Resource
Connecting to the Curriculum
Marking Student Responses
Working with Students
Further Resources
This task is about problem solving a number puzzle.
collection of numbers
 
What is the unknown number in each of these puzzles? There is working space for you to use if you need it.
 
a) Puzzle 1  

If you take my number, multiply it by 3, then add 7, the total will be 52.

 

 

 

 

What is my number? __________
 
b)		  
Puzzle 2  

If you take my number, subtract 10, then divide it by 2, the total will be 16.

 

 
 

 

What is my number? __________
 
c)		  
Puzzle 3  

Five is added to my number and the answer is halved. The total is 11.

 

 
 

 

What is my number? __________
Task administration: 
This task is completed with pencil and paper only.
Copyright: 
Graphic copyright: NZCER
Level:
4
Curriculum info: 
Maths, Number and Algebra, Equations and expressions
Keywords: 
rules, problem solving, linear equations, bedmas
Description of task: 
Students solve puzzles by determining the unknown number from each set of statements.
Curriculum Links: 
This resource can help to identify students' ability to use inverse operations to solve simple linear relationships.
Learning Progression Frameworks
This resource can provide evidence of learning associated with
Using symbols and expressions to think mathematically, sets 4-5
within the Mathematics Learning Progressions Frameworks.
Read more about the Learning Progressions Frameworks.
Answers/responses: 
  Y9 (02/2002)
a) 15 very easy
b) 42 easy
c) 17 easy
Diagnostic and formative information: 
   Common error Likely calculation Likely misconception
b) 21 21 - (10 ÷ 2) = 16 Did not apply BEDMAS.