Binary numbers are the life blood of computer.

You probably know what they look like: a bunch of 1’s and 0’s.

#### Here are some __non__-examples of Binary numbers

- Example 1: 12
- Example 2: 31
- Example 3: 15

#### Here are some examples of Binary numbers

- Example 1: 101101
- Example 2: 101
- Example 3: 10

So how do you tell someone that your number is a binary Number?

I mean 10 could be a binary number or it could “ten”?

In fact, there’s a well known joke that goes like this :

There are 10 types of people in this world. Those that know binary numbers and those that do not.

The entire premise of this joke is that “10” could be a binary number meaning ‘2’, but you would only know that if you understand how to convert binary numbers to decimal numbers.

Usually people write a subscript to indicate that a number is base 2 (binary) like this pictures:

So, that’s what Binary Numbers look like.

The next quesstion to ask yourself is — “Why do Computers use binary numbers?“. If you’d like to know the answer to that question, then go here.