Video: I find the history of numbers so much more fascinating than the application of numbers. Who cares about learning calculus, when you can geek out on the brief history of numerical systems?
Alessandra King shows us how different civilisations came up with different ways to count things, and it's really neat to compare all the different numerical systems (and see how similar they can be). Early civilisations just made simple marks, but as they got more advanced, they needed a system to break down bigger numbers. The Greeks, Hebrew and Egyptians used systems that were just extensions of tally marks with some new symbols added in. The Babylonians, Chinese and Aztec came up with positional notation (the idea that you could re-use the same symbols but they would take on different values depending where they were placed) independently from each other.
But it wasn't until the 8th century, when Indian mathematicians came up with the decimal (base 10) system that we started to get something we use now. Arab conquerors, merchants and scholars spread the base 10 system with Arabic numerals to Europe and it replaced Roman numerals in everyday life around the 15th century. Thank God, maths would have been way harder if it didn't.