Binary numbers are very cumbersome and difficult for humans to deal with. However binary numbers do not convert very conveniently into decimal numbers. Hexadecimal is a number system in which conversions to and from binary are very simple. Hexadecimal is not as easy for humans to work with as decimal, but it is much better than binary.

A single digit can be represented by sixteen possible symbols;
0, 1, 2, 3, 4, 5, 6, 7, 8, 9, A, B, C, D, E, F.

• A is a single digit in hexadecimal, that represents the quantity ten, it is the equivalent of the two digit number 10 in decimal.
• B is eleven.
• C is twelve.
• D is thirteen.
• E is fourteen.
• F is fifteen.

Numbers higher than F (fifteen decimal) require two or more digits, e.g. sixteen is 10 hex, twenty six is 1A hex.

The amount represented by a digit depends on its symbol and its position in the number.

1. A.
2. A5.
3. A67.

The symbol A in the above examples represents;

• ten, in number i).
• one hundred and sixty, in number ii), (ten times sixteen).
• two thousand five hundred and sixty in number iii) (ten times (sixteen squared)).

The weightings of each position in a hexadecimal number, increase by a factor of sixteen, as we move from right to left. i.e. The right hand digit position has a weighting of 160 , with the power increasing by one, for each position we move to the left (161, 162 etc).

The left hand digit has the greatest value and is call the most significant digit.
The right hand digit has the least value and is call the least significant digit. 