Semester 2 Topic 3 Level J

Task Name : Mobile plumber Task Level : J (Year 9)
Semester : 2 Topic : Lines and Coordinates VC Strand : Linear and non-linear relationships
Web Address :
Equipment Needed : Access to a PC/Android device to access number plumber
Victorian Curriculum outcome : Sketch linear graphs using the coordinates of two points and solve linear equations
Task description : Students use Number Plumber to load eight different mobile phone planes. Students input the number of hours of use, and Number Plumber returns a cost (there are only 2 inputs available). Students use these two points to solve the linear equation, finding the cost per hour (gradient) and the base cost (y intercept).
Assessment options : Photograph of handwritten records; screenshots or a screencast.
Teacher notes : Familiarity with the Number Plumber environment is important to make this and other related tasks work. Take some time to learn how to use it yourself and spend some time showing students how to use it. It is like an advanced version of the “algebra machine” ideas with an input and output.
Downloads : Mobile plumber J

Desmos Version

Extension tasks: Desmos Linear tasks set