Tennis ball equations

Tennis ball equations

Pencil and paper
Overview
Using this Resource
Connecting to the Curriculum
Marking Student Responses
Working with Students
Further Resources
This task is about writing and solving number sentences.
 

 


a)

Write the missing number in the box to make the equation correct.
 
3 × + 2 = 14
 
b)
Tennis balls come in cylinders holding 3 balls. Janet has 14 balls.
Use the equation in a) to answer these questions.
 
 
i)
 
ii)
How many cylinders could she completely fill with these balls? __________
 
How many balls would be left over? __________
 
c)
Here is a similar problem:
 
Mikaere has 28 tennis balls altogether. A full cylinder contains 3 balls.
 
 
i)
 
ii)
How many cylinders could he completely fill? __________
 
Write an equation similar to the one above that could be used to find out how many balls John would have left over.
Use a box to represent the number of balls left over.
 
 
Task administration: 
This task is completed with pencil and paper only.
Level:
4
Curriculum info: 
Maths, Number and Algebra, Equations and expressions
Keywords: 
linear equations, number sentences
Description of task: 
Students solve and write simple linear equations about the number of balls in a cylinder.
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: 
 

  

Y8 (09/2000)

a)

   

4

very easy

b)

i)

ii)

4

2

very easy

very easy

c)

i)
ii)

9
Any 1 of:

•   3 × 9 + = 28
•    = 28 - (3 × 9)
•   28 ¸ 3 = 9 r
•   Other algebraically equivalent equations.
[Accept if the box has a "1" in it.]
[The box may be any symbol, e.g., x]

Any 1 of:

•   3 × + 1 = 28
     or 3 × + 1 = 28
•   3 × 9 + 1 = 28
•   Other arithmetic calculations that show 1 as the answer.

easy
2 correct – difficult

1 correct – moderate
Next steps: 
Extension: (Suitable for work in pairs).
Make up two totally different problems, not dealing with tennis balls, but which have similar equations to the two above. Exchange problems with your partner, and check them with each other.