Skip to content # Simplex Locks

## Activity Guide

# This guide looks at the activity in detail and goes into the underlying math.

Myers, Amy. (2020). Simplex Locks. In S. Bowen (Ed.), Math Circle Activity Database. American Institute of Mathematics. https://mathcircles.org/activity/simplex-locks

Contributor(s): Amy Myers

Math Circles: MTC Network, Philadelphia Area Math Teachersâ€™ Circle

- Activity Description
- Topics Covered
- Session Styles
- Mathematical Practices

A simplex lock is a type of combination door lock that involves pushing-in buttons. Given the set of rules for using a 5-button simplex lock, how many different combinations are there?