system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: Bitcoins: How can a math problem be worth money, no matter how hard it is to solve?
gpt
Anything can be worth money. Why is a dollar bill money? It's just paper with an image printed on top. The reason it's valuable is because we all agree that it has value. It sounds silly but there's not much more to it. We give things value when we use them as a medium of exchange, currency has value because of the utility of allowing trade, allowing pricing, allowing us to store value and exchange value easily. If currency has that utility then there is a demand for it that creates a price, and if it has a price then currency can be sold for goods, which creates a supply. 

In that sense, money is just a bunch of tokens for which there is a supply and demand, just like any other good (e.g. pancakes) can be money, only currencies are generally much easier to exchange, divide, store etc.

Now what bitcoin did was essentially take those dollar bills and make them digital through a public ledger. It's still a bunch of tokens for which there is a supply and demand giving rise to a price, only these tokens are digital and thus much easier, faster and cheaper to store or send across the planet for use in payments, and divisible to 8 decimals and thus allowing more precision in pricing, and has its money supply fixed by software and thus not causing the value of the tokens to devalue over time.

The math and cryptography in bitcoin makes sure that unlike normal digital data, you can't copy it infinitely. (that would defeat the point of scarce money. Why accept someone's money for your goods if you can just copy/paste your own money however much you'd like). Bitcoin introduced decentralized digital scarcity, it's quite amazing really. The math doesn't make it have value, we do. But the math makes sure it's secure and that you can't forge bitcoins, that's all.