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If you take a close look at the world, you’ll find that you’re surrounded by ancient history. There are lots of great examples of this, but today we’re going to talk about one example in particular that’s near and dear to my—and hopefully your—mathematical heart: Roman numerals. These ancient numbers can still be seen all over the place—on signs, clocks, monuments, and even in movie credits! But who came up with this number system? Was it really the Romans? How exactly does it work? And why is it still used for certain things? Stay tuned because those are precisely the questions we’ll be answering today.

Where Do Roman Numerals Come From?
The story of Roman numerals actually begins way back in the distant past alongside the story of the so-called tally-bones that we talked about in the last episode called How to Add and Subtract Like an Egyptian. As you’ll recall, the story of tally-bones begins at least 30,000 years ago when people began making notches in bones as a way of counting. The problem with this method is that it doesn’t work well for large numbers since it’s tough to tell at a glance exactly how many notches you’ve carved. So, long ago, a tally-bone carver had an ingenious idea to make every fifth notch in the shape of what many centuries later would look like the letter “V.” This clever change meant that you could now quickly count-up most of the notches on a tally-bone by counting groups of 5—something like “5, 10, 15, 20, 21, 22” instead of counting each individual notch up to 22. Much faster!

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