Currency in Harry Potter series consists of three different coins. In decreasing order of value, they are: Galleon, Sickle and Knut. They are Gold, silver, and Bronze, respectively. According to Rubeus Hagrid, there are 17 Sickles in a Galleon, and 29 Knuts in a Sickle, meaning there are 493 Knuts to a Galleon.
Since that Wizarding Currency are made of Gold, Silver and Bronze, J. K Rowling wrote that ’Money’ in itself is thought to be one of the five exceptions to Gamp’s Law of Elemental Transfiguration, meaning it CANNOT be created from nothing.
So, how is it possible that our Muggle Money a.k.a Paper/Fiat Money can‘Magically’ multiplies its value out of nothing when it is made of Paper, Plastic & Digital number?