IsRational()

# a third is itself
? (new stzNumber("1/3")).Content()
# two quarters reduce
? (new stzNumber("2/4")).Content()
# six thirds reduce past being a fraction at all
? (new stzNumber("6/3")).Content()
# ...and report themselves as an integer
? (new stzNumber("4/2")).Representation()
# a zero numerator is just zero
? (new stzNumber("0/5")).Content()
# the sign lives on the numerator
? (new stzNumber("-1/2")).Content()
# ...even when it was written on the denominator
? (new stzNumber("1/-2")).Content()
# a fraction knows what it is
? (new stzNumber("1/3")).Representation()
# ...and answers the predicate
? (new stzNumber("1/3")).IsRational()
# while a decimal does not
? (new stzNumber("0.5")).IsRational()