How do I formulate a ratio for excel

[Guest]

I have to formulate a ratio of males to females
Males=40248 Females=37999

 

[Myrna Larson]

=40248/37999

and possible=y format with this custom format

0.00" to 1"

 

[Dave Peterson]

Maybe a custom format like this if you could use the /:
???/???
(up to 3 digits)

or if you have to use a colon:
=substitute(text(a1/b1,"???/???"),"/",":")

The first suggestion results in a number. The second results in text.