Numeric literals are frequently used. They represent a number that your program will need to work with. Most of the time you will use numbers in base ten-the base that everyone uses. However, Perl will also let you use base 8 (octal) or base 16 (hexadecimal).

**Note:**
For those of you who are not familiar with non-decimal numbering systems, here is a
short explanation. In decimal notation-or base ten- when you see the value 15 it
signifies (1 * 10) + 5 or 15_{10}. The subscript indicates which base is being
used.

In octal notation-or base eight-when you see the value 15 it signifies (1 * 8) + 5
or 13_{10}.

In hexadecimal notation-or base 16-when you see the value 15 it signifies (1 * 16) +
5 or 21_{10}. Base 16 needs an extra six characters in addition to 0 to 9 so that
each position can have a total of 16 values. The letters A-F are used to represent
10-15.

So the value *BD _{16}* is equal to (

If you will be using very large or very small numbers, you might also find scientific notation to be of use. Scientific notation looks like 10.23E+4, which is equivalent to 102,300. You can also represent small numbers if you use a negative sign. For example, 10.23E-4 is .001023. Simply move the decimal point to the right if the exponent is positive and to the left if the exponent is negative.