Factorise algebraic expressions by identifying numerical factors (ACMNA191)

LO: To factorise algebraic expressions.

  • What an expression is
  • The four basic operations of numeracy


  • That factorising algebraic expressions is the opposite of expanding algebraic expressions.


  • I can factorise algebraic expressions.

Essential Questions:

  • How can expressions be factorised?

Factorising an Expression

Factorising an expression is the opposite of expanding an expression.
To factorise an expression you have to find common factors (what is similar between the two), between the terms and pull them out.

When you expand the expression out, it’s called the distributive law.

3ab + 9b can be factorised into 3b (a + 3) because 3b is common to both terms and can be removed to simplify the expression.

How to Factorise Expressions

Factorising Expressions Videos

Student Generated Videos

Textbook Questions

My Maths 8

Ex 4G pg. 216 Q. 5-6

My Maths 9

Ex 2F pg. 79 Q. 3-4, 6

My Maths 10

Ex 2D pg. 73 Q. 1