a man forgot the last 2 digits of a phone number.

he only remembers that they are different

and they are odd

what is the chance that he will pick the correct combination of numbers

of the original phone number

$\displaystyle \frac{\binom{5}{1}\cdot \binom{4}{1}}{\binom{10}{2}}=\frac{2}{9}$

is it a correct expression?