System of representing numbers as multiples
of the appropriate base raised to some power;
for example, the number 97.8 can be expressed
as 0.0978 x 10^3 or 9780 x 10^-2. In
computing, the number is expressed as a
decimal fraction, so 97.8 becomes 0.978 x
10^2. See fixed-point notation. In a
computer, the numbers are represented by
pairs; 97.8 = (.978, +2). The first number of
the pair is called the mantissa and the
second the exponent. The definition applies
equally to numbers expressed to a different
base (for example, binary fractions muliplied
by two raised to some power). The advantage
of floating-point notation is that very large
and very small numbers can be expressed with
a few digits. Thus (.978, +18) written out in
full would require 15 digits (978 followed by
18 zeros).