Find the Least Common Denominator (LCD) of improper fraction
and
.
Find the Least Common Multiplier of 9 and 3.
\Multiples of 3: 3,6,9,12,15,18,......
\Multiples of 9: 9,18,27,......
\The least common multiple of 3 and 9 is 9, the LCD is 9.
\Rewrite each fraction using the least common denominator (LCD).
\
and 
Rewrite the difference using the LCD.
\
\
(Subtract:
)
The difference is
.