Hexadecimal is quite simply, a counting system.
As humans, we’re familiar with the decimal system. There are ten decimal digits, 0 to 9. Every number is made up of these digits.
When we count in decimal, and we get up to 9, we just add a new digit, ‘1’, to the front and start the second digit back at zero. Any time we run out of numbers, we just add a ‘1’ to the front.
While we use decimal, computers use binary and hexadecimal. Hexadecimal uses 16 digits, 0 to ‘F’. All hex numbers are made with these digits.
If we’re counting, we get up to ‘F’, then add a ‘1’ as a new column, and start the first column back at zero.
This new number looks like the decimal number ‘ten’, but’s it’s not. It’s actually the equivalent of the decimal number ‘sixteen’.
So to avoid this confusion, hex numbers often start with ‘0x’ or end with ‘h’. For example, ‘0x10’ or ‘10h’. This way, we know they’re hexadecimal, not decimal.