Constants used in numeric expressions or as arguments
to functions can be integer or noninteger, depending on the application
or function.
You can specify as many digits in a constant as needed
as long as you understand the precision restrictions of your computer.
Numeric constants can be signed (+ or –) but
cannot contain any other special characters, such as the comma or
dollar sign.
Numeric constants can be expressed with scientific
notation. Thus, the exponent for a constant in scientific notation
is limited to two digits. The range of values allowed for exponents
in scientific notation is from –99 to +99.