This engaging thinking task is designed to promote deep mathematical thinking, collaboration, and discourse in line with Peter Liljedahl’s Building Thinking Classrooms in Mathematics. Students are challenged to explore how many unique 3-digit locker codes can be created using the digits 1 through 5, with specific constraints on repetition and order.

Students work in randomly assigned groups using vertical non-permanent surfaces (whiteboards or posters) to solve the problem using a variety of strategies, including listing, visual diagrams, and multiplication reasoning. The task also includes open-ended extension challenges that allow students to further apply their reasoning to variations of the problem.

What’s Included:

• Teacher instructions and facilitation strategies

• Power point Presentation
  
• Extension challenges for differentiation
  
• Complete answer key with detailed explanations
  

Learning Goals:

• Encourage mathematical reasoning and flexible thinking
  
• Foster collaboration and discussion
  
• Support multiple entry points and multiple solution paths
  
• Promote student autonomy and engagement in problem-solving
  

Perfect for warm-ups, math stations, or rich tasks during a problem-solving unit!