# Numeral Systems and the Place-Value notation

To start with, understand that numbers can be represented in different ways. If I showed you tally marks like this you know I'd mean the number five. But, that's the way to write it in one numeral system ((unary, if you must know.)). Simply put, a numeral system is a consistent way to write a number using a certain set of characters (marks, letters, numerals, etc.). The system dictates which characters are used and how they are used to represent a number. It's an old one, but consider the Roman numeral system. You've probably seen the characters (I, V, X, L, C, etc.) and know that "III" is three and "IV" is four, and so on. This is an example of an earlier system using Roman characters and an additive-notation - that places characters left-to-right -…