Know More About Worksheets on Rational expression word problems Moreover, we know 0 can be written as 0/1, we observe that both 0 & 1 are integers and the denominator i.e. ‘1’ ≠ 0. So we conclude that ‘0’ is a rational number and not irrational. An irrational number is any real number that cannot be expressed as a ratio a/b, where a and b are integers and b≠0 and it is not a rational number. That means an irrational number cannot be represented as a simple fraction.