Irrational number

An irrational number is a real number that cannot be expressed as the ratio of two integers. Equivalently, an irrational number, when expressed in decimal notation, never terminates nor repeats. Examples are etc.

Because the rational numbers are countable while the reals are uncountable, one can say that the irrational numbers make up "almost all" of the real numbers.

See Also

• Algebraic number
• Rational number
• Transcendental number

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