How do coins let people trade with strangers?

Coins work because they are portable value that everyone agrees on. Imagine you have a shiny red marble and your friend has a blue one; if you both like marbles equally, you can swap them without needing anyone else’s permission. Coins act like those universally liked marbles for bigger items.

Long ago, if I gave you a gold coin, you had to worry it was fake or light on weight. Today, we trust the government stamp that says "one dollar." This is called fiat money. It means the value comes from our shared belief, not just the metal itself. Think of it like a VIP pass at a theme park. The paper isn't worth much, but you know it gets you on the ride because everyone else accepts it.

Before coins, people traded goods directly. If you had apples and wanted shoes, you had to find a shoemaker who also wanted apples right then. This was hard! Coins solve this by being a medium of exchange. Now, I can sell my apples to anyone for coins, and then take those same coins to the shoemaker later, even if they don't care about apples.

Coins are like portable tokens of trust. They let us trade with strangers because we all agree on what the metal is worth, turning complex deals into simple swaps.