Competitions

Proof Writing — Proofs

Write each proof out in full before revealing the model solution. Compare structure, not just the idea: did you state the assumption, name the method, and end with the conclusion?

Problem 1 of 43
Contradiction

Prove that log⁡23\log_2 3 is irrational.

Write a full proof on paper. There is no answer box — when you are ready, reveal the solution and compare your argument.

Proof practice — Proof Writing