As mentioned above, the hexadecimal system uses 16 digits. This is where we run into a potential problem. In our traditional way of writing numbers we use the decimal numbers 10, 11, 12, 13, 14, and 15, which consist of two symbols put together. So if you were to use the number 10 in hexadecimal notation, it would be unclear what you mean.

To avoid this problem, the letters A through F are used to represent the numbers ten through 15 in the hexadecimal system. So in total, the numbers **0 through 9** and **A through F** are used to represent the equivalents of binary numbers and decimal numbers. There are various notations available for distinguishing hexadecimal numbers from decimal numbers:

- 73
_{16} - 73
_{hex} - 73h
- 73H
- 73H
- 0x73
- $73
- #73
- "73
- X’73’

The prefix *0x* and the suffix *h* are especially common in programming, and the dollar prefix *$* is frequently used in certain processor families in assembly language.