Curious Kids is a series for children of all ages. If you have a question you’d like an expert to answer, send it to curiouskidsus@theconversation.com.

Why do money and trading exist? – Vanessa C., age 10, Gilbert, Arizona

Imagine a world without money. With no way to buy stuff, you might need to produce everything you wear, eat or use unless you could figure out how to swap some of the things you made for other items.

Just making a chicken sandwich would require spending months raising hens and growing your own lettuce and tomatoes. You’d need to collect your own seawater to make salt.

You wouldn’t just have to bake the bread for your sandwich. You’d need to grow the wheat, mill it into flour and figure out how to make the dough rise without store-bought yeast or baking powder.

And you might have to build your own oven, perhaps fueled by wood you chopped yourself after felling some trees. If that oven broke, you’d probably need to fix it or build another one yourself.

Even if you share the burden of getting all this done with members of your family, it would be impossible for a single family to internally produce all the goods and provide all the services everyone is used to enjoying.

To maintain anything like today’s standard of living, your family would need to include a farmer, a doctor and a teacher. And that’s just a start.

Economists like me believe that using money makes it a lot easier for everyone to specialize, focusing their work on a specific activity.

A farmer is better at farming than you are, and a baker is probably better at baking. When they earn money, they can pay others for the things they don’t produce or do.

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