What's the symbol for five?

**5**

What's the symbol for ten?

**10**

But wait, isn't that the symbol for one and zero?

Right, so in our numbering system, when we get to the number ten, we write the symbol for one and zero. There is no symbol for ten, we simply recycle the symbols we already have. Because of this we call our numbering system "base-ten", or "decimal".

"Ones and zeros", "true and false", and "on or off" are all terms you have probably heard before. What these are all referring to is a

*different*kind of numbering system. For our decimal system, we write a '10' when we get to ten, but for binary, we write a '10' when we get to two. There is no symbol for two in binary, exactly how there is no symbol for ten in decimal. "On" or "off" simply refers to '1' or '0' in binary.