Cellphone Confusion


This is a level 4 measurement strand activity from the Figure It Out series.

A PDF of the student activity is included.

Achievement Objectives
GM4-2: Convert between metric units, using whole numbers and commonly used decimals.
GM4-4: Interpret and use scales, timetables, and charts.
Student Activity


Click on the image to enlarge it. Click again to close. Download PDF (403 KB)

Specific Learning Outcomes

work with rates and make comparison

Required Resource Materials


FIO, Level 4, Measurement, Book One, Cellphone Confusion, pages 15-16


This activity loosely mirrors the complex deals being offered by cellphone companies. The maths in the activity is quite intricate, and the students will need to read the information with care so that they take all factors into account.
The facts can be collated in a spreadsheet or a table. This will help the students to sort out the information as they answer the questions.

Cellphone companies have their rates posted on the web, so this is where the students should go when answering question 6. A proportion of the class will already be regular cellphone users and will be able to establish a “profile” for themselves against which to check the different plans available.
As an extension activity, your students could create a survey to find out:

  • the proportion of students who have phones
  • who pays for student phones and their use
  • how much students are spending on cellphones.

This information could be collated and presented using charts or a computer.

Cross-curricular links

As cellphones become more sophisticated, the social implications of their use become greater and more widespread. This activity could be part of a cross-curricular unit using achievement objectives from the science, social studies, and technology curricula. As part of this, students could:

  • find out how cellphones work
  • investigate the history and evolution of the telephone
  • investigate the social changes occurring as a result of this technology
  • consider cellphone etiquette and safety issues
  • debate the proposition that their use should be banned during the school day
  • predict what further changes in phone technology might be in store and what the effects of such changes might be. They could consider what might be lost as well as what might be gained from such developments.

Achievement Objectives


  • investigate and describe how selected items of everyday technology work and affect our lives (Making Sense of the Physical World, level 3)
  • investigate and offer explanations of how selected items of technology function and enhance everyday activities of people (Making Sense of the Physical World, level 4)

Social Studies
Demonstrate knowledge and understandings of:

  • the impact of the spread of new technology and ideas on culture and heritage (Culture and Heritage, level 4)


  • • explore and discuss the impacts over time on the local and wider environments and society of some specific technology, as in the dairy industry; the introduction of wide-bodied jets (Technology and Society, level 4)

Answers to Activity

1. a. i. $63.90
Peak calls: 20 min x 0.99 = $19.80
Extra off-peak calls at standard rates: 90 min x 0.49 = $44.10
ii. Text messages: 105 x 0.20 = $21.00
iii. $109.90. (25.00 + 63.90 + 21.00)
b. $1,318.80. (12 x 109.90)
2. a. $45.80
Peak calls: 20 x 0.99 = $19.80
Extra off-peak calls at standard rates: 40 min x 0.65 = $26.00
b. $16.50. (110 x 0.15 = $16.50)
3. a. $62.30
b. $1,017.60.
(3 months x 62.30 a month = $186.90; 9 months x 92.30 = $830.70;
total for the first 12 months is 186.90 + 830.70 = $1,017.60.)
4. a. Busy Lines
b. Yes. (After 24 months at this rate of usage, the charge from YY would be $2,637.60 and the charge from BL would be $2,125.20.)
5. Busy Lines is cheaper in each case.
(12 months: YY = $1,418.80; BL = $1,217.60; 24 months: YY = $2,737.60;
BL = $2,325.20)
6. Results will vary.


Log in or register to create plans from your planning space that include this resource.