This activity gets students to work through a series of algebra questions to find the combination that will unlock the code. In groups, or individually, students must work through each set of questions, which encourages them to practise simplifying expressions, collecting like terms, factorising expressions and expanding expressions. Once each set of questions are completed, they must add up some part of each answer (this is specified in each set) to find a total. The final digit in the total will become one digit of the combination. Once students believe they have all four digits, they can attempt to unlock the lockbox. This activity can encourage collaboration or individual work. It is recommended that no calculators are allowed, to create a more challenging task for students.

Equipment Required:

• Small Toolbox/Lockable Box
• 4 Digit Combination Lock
• Prizes

Australian Curriculum Links:

• Extend and apply the laws and properties of arithmetic to algebraic terms and expressions (ACMNA177)
• Extend and apply the distributive law to the expansion of algebraic expressions (ACMNA190)
• Factorise algebraic expressions by identifying numerical factors (ACMNA191)
• Simplify algebraic expressions involving the four operations (ACMNA192)
• Apply the distributive law to the expansion of algebraic expressions, including binomials, and collect like terms where appropriate (ACMNA213)