Learning Objectives

• Identify counting as a problem-solving tool in computer science.
• Apply basic counting principles to simple CS scenarios.
• Distinguish between permutation and combination in context.
• Use binary counting to represent small sets of values.
• Explain how counting helps estimate possibilities in computing tasks.

Materials Needed

• Whiteboard and markers
• Timer
• Center instruction cards
• Student recording sheet
• Deck of cards or colored counters
• Small paper slips or sticky notes
• Calculators optional
• Exit reflection sheet or notebook paper

Support

• Use small numbers and visuals for all counting tasks.
• Provide sentence starters such as 'Order matters because...'.
• Allow students to work in pairs at every center.
• Offer pre-filled tables or partial lists for students who need extra structure.
• Review vocabulary before centers begin.

Challenge

• Ask students to generalize patterns from one center to a formula or rule.
• Include a larger password scenario with repeated choices or more character options.
• Have students explain why two different methods produce the same total.
• Add a challenge card: 'How would the count change if repetition were not allowed?'

Checks for Understanding

• Observe center work and listen for correct use of vocabulary.
• Ask quick oral questions during transitions.
• Review student recording sheets for accuracy and reasoning.
• Use a final share-out to confirm understanding of permutation, combination, and binary basics.

Closure

Summarize that counting helps computer scientists measure possibilities, design code, and reason about systems. Reinforce that order matters in some situations and not in others, and that binary is the foundation of digital representation.