Hey kiddo! Do you know what money is? It's something that we use to buy things we want or need, like toys or food. But did you know that money can be different in different parts of the world? That's where something called the Petrograd standard comes in.
Petrograd is a city in Russia, and a long time ago, they had a certain type of money that they used called the ruble. The Petrograd standard was a way of measuring how much the ruble was worth compared to other types of money used in other countries.
It's kind of like when we use inches or centimeters to measure things like height or length. The Petrograd standard was like a ruler for money.
So when people from other countries wanted to trade with Petrograd, they needed to know how much their money was worth in rubles. That's where the Petrograd standard came in handy. It helped people know how much they needed to trade in order to get the same value.
Nowadays, we have other ways of measuring currency value, but the Petrograd standard was an important system in its time. It helped make trade and commerce easier between different countries, and made sure that everyone could understand how much their money was worth. Pretty cool, huh?