Converting a decimal (base 10) number to hexadecimal (base 16) is a two-step process: first, the decimal number is divided by 16 and the remainder is noted, and then the quotient is divided again by 16 and the remainder is noted, and so on until the quotient becomes zero.

Here’s an example of how to convert the decimal number “255” to hexadecimal:

- Divide 255 by 16. The quotient is 15 with a remainder of 15.
- Divide 15 by 16. The quotient is 0 with a remainder of 15.
- Write down the remainder from each step as the next digit in the hexadecimal representation. In this example, the remainder is 15. Since 15 is represented by the hex digit “F” the hex representation of 255 is “FF”.

Another way to convert decimal to hexadecimal is by using the built-in functions of programming languages like python, for example, you can use hex(255) to get the hexadecimal representation of the decimal number 255

In general, to convert a decimal number to hexadecimal, you can use the following steps:

- Divide the decimal number by 16 and store the remainder.
- Divide the quotient of the previous step by 16 and store the remainder.
- Repeat step 2 until the quotient is zero.
- Write down the remainder in reverse order (from the last step to the first step) as the digits in the hexadecimal representation.
- Use the corresponding hexadecimal digits (0-9 and A-F) for the remainder from step 4.

It’s important to note that Hexadecimal numbers use the digits 0-9 and A-F to represent the numbers from 0 to 15, in decimal notation.