Hexadecimal to Binary is a trivial conversion. Each hexadecimal digit can be directly converted to its four bit binary equivalent, using a Binary/Hexadecimal Table if necessary.
For example the hex number FACE16 can be converted by converting F to 1111, A to 1010, C to 1100 and E to 1110. The binary number is then simply 1111101011001110.
Another example: Convert the hexadecimal number 8AD0 to binary.
The answer is 1000101011010000. 8 is 1000. A is 1010. D is 1101. 0 is 0000. This gives us the binary number 1000101011010000.
Next: Non-Decimal Arithmetic