Here's how you count in binary. Click on next number below and notice that you only use the digits 0 and 1 and then switch to the next column:
In regular decimal numbers, we use powers of 10 and the digits 0-9. In binary numbers, we use powers of 2 and just the digits 0 and 1. To convert binary numbers to decimal numbers, you add up the corresponding powers of 2. Try to convert a number below.
When you type in letters and other characters on a keyboard, each one is represented as a number using ASCII or UNICODE encoding. For example, here is the ASCII numbers for common letters:
Each one of these decimal numbers is then saved in binary code.
Here are some online converters to convert between binary, decimal, and ASCII: