Math::BigRat implements the following methods.

new(*value*)

Creates a new Math::BigRat object. You can use all types of input for
`new()`: `'3/5'`,
`'2/33'`, `'6/9'`, etc.

denominator()

Returns a copy of the denominator as a positive BigInt:

my $rat = Math::BigRat->new('2/7')
print $rat->denominator(), "\n"; # Prints 7

numerator()

Returns a copy of the numerator as a signed BigInt:

my $rat = Math::BigRat->new('2/7');
print $rat->numerator(), "\n"; # Prints 2

parts()

Returns a list consisting of a signed numerator and unsigned
denominator. Both are BigInts.

my($n, $d) = $rat->parts(); ### Ewwww, rat parts!
print "numerator: $n\n";
print "denominator: $d\n";