Okay kiddo, have you ever heard of the Ionian Obol? It's actually a very old, ancient currency that people used to use a long, long time ago.
So, imagine that you have a toy that you really love and you want to buy another toy that costs $5. But, you only have $2. That means you're going to need more money, right? Well, back in the day, people used the Ionian Obol to help them buy things that they didn't have enough money for.
The Ionian Obol was a small, silver coin. It was so small that you could fit it in the palm of your hand. And, it was worth one-sixth of a drachma. A drachma was a bigger coin that was worth more money than the Ionian Obol.
People would use the Ionian Obol to make up the difference if they didn't have enough drachmas to buy something. For example, if they needed five drachmas to buy a new shirt, but they only had four drachmas, they could use the Ionian Obol to make up the difference.
Nowadays, we don't use the Ionian Obol anymore because we have different kinds of money. But, it's still a really cool thing to learn about and remember how people used to buy things a long, long time ago!