Two students agree to meet up in a bar. They are both trying to be very precise, and try to arrive at exactly the right time, but arrive 29 minutes apart. An example of the ambiguities of language unfolds, which shows why mathematics needs to use algebraic symbols. Marcus du Sautoy sets the problem in this puzzle panel game.
Pose the puzzle to the students first and see if they can work out the solution before showing the full clip, then play it. Could be used as a starter activity before lessons involving time. Discuss the problems of language, and how algebraic notation is an attempt to avoid any ambiguities.