Texas Instruments: Numb3 Rs: Is This Seat Taken?

Based off of the hit television show NUMB3RS, this lesson introduces students to permutations, factorials, and counting principle. The lesson is framed in the context of a wedding, in which (at first) people are arranged to sit in a line, with certain restrictions; later, people are to sit around a table, again with certain restrictions. The extensions to this lesson provide some challenging follow-up problems.