The easiest way to see it is like this: Lets say you make chairs. Someone pays you 100$ for a chair. You make the chair with a small amount of materials, and se

The easiest way to see it is like this: Lets say you make chairs. Someone pays you 100$ for a chair. You make the chair with a small amount of materials, and sell it to the buyer for 100$. At the start of this process, there was 100$ and maybe 5$ of materials. After the transaction, the 100$ is still there, but there is also a chair worth 100$ in circulation. So 105$ of assets turned into 200$.