Number Systems • Class 9 Mathematics • NCERT • CBSE
Irrational numbers are real numbers that cannot be expressed as a fraction p/q, where p and q are integers and q ≠ 0. Their decimal expansions are non-terminating and non-repeating. Examples include √2, √3, π, and e. They are denoted by Q' or ℝ\Q.
Irrational numbers: cannot be expressed as p/q (q ≠ 0)
√n is irrational if n is not a perfect square
√2 × √2 = 2 (rational — product of two irrationals can be rational)
R = Q ∪ Q' (Real numbers = Rational ∪ Irrational)
GyanAI's AI tutor can answer any question about this topic instantly. Try GyanAI free for step-by-step NCERT solutions aligned with the CBSE curriculum.