Sum of List Relay
Find the sum of a sequence of numbers. Posed as a relay problem. A non-relay version is available at http://www.geogebratube.org/student/m142500.
The adding up of a list of numbers doesn't sound much like a counting problem, but there is some counting involved in finding the solution. A video of some simple addition (1 + 2 + 3 + ... + n) is found at http://www.artofproblemsolving.com/Videos/external.php?video_id=60