IB skill practice

Use the pigeonhole principle

Apply pigeonhole reasoning to prove existence results and counting constraints.

Paper 1, Paper 2 5 marks Difficulty 3

Use the pigeonhole principle - pigeonhole principle item

Case B2. Use the counting-grid visual to calculate the forced occupancy, matching, or threshold value.

Worked practice: result and interpretation

Calculate the requested result first, then choose the interpretation that follows from it.