MATRIX MULTIPLICATION
Year 11 Maths – General Maths
Australian Curriculum learning objectives
ACMGM0161 - Use matrices, including matrix products and powers of matrices, to model and solve
problems; for example, costing or pricing problems.
Resources required
 Introduction to Matrices2 captioned online video and projection facilities. (Duration: 12
minutes)
 Milkshakes and Matrix Multiplication3 captioned online video. (Duration: 4 minutes)
 Milkshakes and Matrix Multiplication worksheet × class set
Lesson outcome: students learn what a matrix is and how matrices can be added, subtracted
and multiplied.
Lesson outline
1.
Prior knowledge quick think: When do we put numbers from real-life situations into tables?
[Hints: sports results; taking stock of items in the supermarket; price lists; school attendance
figures]
2.
Why would we want to add, subtract or multiply the numbers in these tables? [Hints: latest
sports results; items sold; deliveries received; calculating bills]
3.
Summarise answers to prior knowledge activity and introduce Introduction to Matrices video.
4.
Students are to write down the notation that is used for matrices. They should also write
down an example of adding, subtracting, multiplying by a scalar, and multiplying two
matrices together. Certain sections of the video may need to be replayed for students to
complete this task.
5.
Discussion: The way that matrices are added and subtracted seems obvious. Multiplying a
matrix by a scalar is also straightforward. But why do we multiply two matrices together in
the way that is described in the Introduction to Matrices video?
6.
Students read through the Milkshakes and Matrix Multiplication worksheet and view the
Milkshakes and Matrix Multiplication video.
Homework/extension
Students view Milkshakes and Matrix Multiplication captioned online video and complete page 2 of
the worksheet.
Opportunity for further activity
A learning journey4 is available from Scootle.
1
http://bit.ly/1rvA1eQ
http://www.youtube.com/watch?v=xyAuNHPsq-g
3 http://www.teachertube.com/viewVideo.php?video_id=334236
4 http://www.scootle.edu.au/ec/search?q=matrices&field=title&field=text.all&field=topic
2