You would find the Area the same way as if they were whole numbers.
Area = Length x Width
If the fractions are mixed numbers, then convert them to improper fractions.
Example: Length = [tex] \frac{1}{2} [/tex], Width = 1 [tex] \frac{2}{3} [/tex]
Area = [tex] \frac{1}{2} [/tex] x 1 [tex] \frac{2}{3} [/tex]
= [tex] \frac{1}{2} [/tex] x [tex] \frac{5}{3} [/tex]
= [tex] \frac{5}{6} [/tex]
Hope this heps!