This is a maths problem I am not sure, but I know that normal paper money is approximately $1\text{mm}$ thick. But why is there $100$ notes in a $1\text{cm}$ thick paper money stacked in say banks? Wouldn't $1\text{mm}$ thick paper money imply that $1\text{cm}$ should be $10$ paper money stacked on top of each other? What am I missing here?
(This is not a random question, I genuinely do not know why this is the case and I have no suitable place to ask at this point in time).