It's not too difficult to work out, actually. Consider that the reason hexadecimal notation is used in the field of information technology has to do with the fact that "hexadecimal" is another way of saying "base 16", and the binary representation of decimal 16 (hexadecimal 10) is 10000.

There are 16 symbols in hexadecimal : 0,1,2,3,4,5,6,7,8,9,A,B,C,D,E,F
The only thing you need is to make a table with these relationships to binary, that is:
0 = 0000
1 = 0001
2 = 0010
3 = 0011
.........
F = 1111

So, C0F is the equivalent to binary:
C -> 1100
0 -> 0000
F -> 1111

merge them:

C0F -> 110000001111

The inverse (binary to hexadecimal)

0011100= (we want groups of four, so we add a zero to the left)
00011100=
0001,1100=
1C