In addition to simplifying the numerator and the denominator in a fraction, it is
mathematical convention to rationalize the denominator--that is, to write the
fraction as an equivalent expression with no roots in the denominator.
To rationalize a denominator, multiply the fraction by a "clever" form
of
1--that is, by a fraction whose numerator and denominator are
both equal to the square root in the denominator. For example, to
rationalize the denominator of

, multiply the
fraction by

:
×
=
=
= 
.
Thus,
= 
.