It relies only on the ability to add and multiply by 2. This could be a fun math lesson to explore at the end of the year to demonstrate an alternative method to multiplication. This method is not meant to be demonstrated as a primary method of multiplying, but rather to show how the use of numbers has changed over time and culture. This would be great if Ancient Egypt is a topic that you have been exploring with your class.
Check out the tutorial below to see how it works.