Numerator( rat )
Numerator returns the numerator of the rational rat. Because the
numerator holds the sign of the rational it may be any integer. Integers
are rationals with denominator 1, thus Numerator is the identity
function for integers.
gap> Numerator( 2/3 );
2
gap> Numerator( 66/123 );
22 # numerator and denominator are made relatively prime
gap> Numerator( 17/-13 );
-17 # the numerator holds the sign of the rational
gap> Numerator( 11 );
11 # integers are rationals with denominator 1
Denominator (see Denominator) is the counterpart to Numerator.
GAP 3.4.4