The crossword solution for the term 'Proof Problem' is TYPO. A proof problem is a type of problem in which one must prove that a statement is true or false. This type of problem is often used in mathematics and logic to test a student's understanding of the subject. A TYPO is an error in a written document, usually caused by a mistake in typing or writing. In this context, a TYPO could be seen as a proof problem, as it requires the reader to identify and correct the mistake.