Rational Numbers A rational number is a number that can be written as a ratio.
That means it can be written as a fraction, in which both the numerator (the number on top) and the denominator (the number on the bottom) are whole numbers.
irrational not expressible as a ratio of two integers, and having an infinite and nonrecurring expansion when expressed as a decimal.
Examples of irrational numbers are the number π and the square root of 2.
