Year 4

# Multiplication: Cartesian Product

Students create avatars and explore animals in a mix and match book. The key idea of multiplication as a Cartesian product is introduced.

This is a classic reSolve sequence aligned with the Australian Curriculum V8.4. It is only available as a downloadable package.

Students are introduced to the key idea of multiplication as a Cartesian product, using the language of “for each”.

This sequence is for students who:

• have previously used arrays to help solve multiplication problems.
• are building their recall of multiplication facts up to 10 x 10.
• ideally have worked on multiplication problems that involve multiplying three or four numbers together and questions that use at least one multidigit number.

### Lesson 1: What is a Plocoroo?

Students explore the number of animals it is possible to make using a mix-and-match book. The book contains 10 different animals that have each been divided into three parts: head, body and tail. To help solve the larger problem, students are encouraged to use a simpler problem. They use a tree diagram in their working.

### Lesson 2: Making Avatars

Students design their own avatar by choosing options from a set of features. The class is asked to consider if all possible avatars have been made, given the different features that can be selected. Students use an array and are then introduced to a tree diagram to explore the Cartesian product for multiplication.

Last updated June 19 2020.

This is a classic reSolve sequence aligned with the Australian Curriculum V8.4. It is only available as a downloadable package.