Ruby program to get the numerator from a rational number

num1 = Rational(21, 7);
num2 = Rational(-7, 20);
num3 = Rational(21);

print "Num1 numerator: "  ,num1.numerator();
print "\nNum2 numerator: ",num2.numerator();
print "\nNum3 numerator: ",num3.numerator();

Output:

Num1 numerator: 3
Num2 numerator: -7
Num3 numerator: 21