rational number

noun

, Mathematics.

1. a number that can be expressed exactly by a ratio of two integers.

rational number

noun

1. any real number of the form a / b , where a and b are integers and b is not zero, as 7 or 7/3

rational number

1. A number that can be expressed as an integer or a quotient of integers. For example, 2, −5, and 1 2 are rational numbers.

Word History and Origins

Origin of rational number¹

First recorded in 1900–05

Example Sentences

And the box “What Are Imaginary Numbers?” should have said that rational numbers include the integers, not that “rational numbers are the integers.”

From Scientific American

Even such bonkers-looking numbers, however, together with all the rational numbers, make up only a tiny fraction of the real numbers, or numbers that can appear along a number line.

From Scientific American

If the two new arrangements contained repeating patterns, the length of their translation vectors should have been related to each other—specifically, their ratio should have been a rational number.

From Scientific American

The conjecture predicts that the corresponding field will be “the smallest field that you get by taking sums, products and rational number multiples of these roots,” Arthur says.

From Scientific American

Even the rational numbers—the set of numbers that can be written as a/b for integers a and b—were countable.

From Literature