For our first math unit, we went back in time to the very beginning – how numbers were invented. As our reference book, we used Think of a Number by Johnny Ball (published by Dorling Kindersley).
We practiced writing Babylonian numbers on clay, made Mayan numbers using popsicle sticks, beans and shells, and played an online version of the ancient Egyptian board game Senet (www.ancientegypt.co.uk).
We watched a few online videos about these ancient number systems: History of Mathematics on YouTube and Discovering Math: Reading and Writing Mayan Numbers on HowStuffWorks.
We played a game using our home made ancient numbers flash cards (can’t learn a unit without any games!).
And of course, the kids each made a lapbook about how numbers were invented. I’d say this was a mini-unit for us. We didn’t delve into it too deeply and for too long (spent 2 weeks on it). It was, however, a good way to learn about the purpose of numbers in our lives, and how our lives would be so different (and difficult) without them.