Question

How do i represent hex 1A in binary with 8 bits?

Answer 1

In hexadecimal representation, each 'digit' requires four bits (16 different values). In your example, '1A', you will need four bits to represent '1' and four bits to represent 'A'.

If you examine the hexadecimal number starting from the right (the least-significant digit), you will encounter the 'A'. What is the binary representation of 'A' (or 10)? Write down those bits. Then you move one digit to the left and you encounter '1'. What is the binary representation of '1'? Write down those four bits to the left of the four bits that represent 'A'. There's your answer. This will even work for larger numbers like '4D8F23' (which will need 24 bits).

An alternative method would be to convert the hexadecimal number to a decimal number and write that decimal number as a binary number. This alternative method may appear to be easier, but in the special case of hexadecimal numbers, I'd say the first method is far easier then the alternative.