Skip to main content
rational number

rational number

1 3.8
A number that can be written as a fraction like 3/4 or -1/2
  • noun
  • /ˈræʃənl ˈnʌmbər/
  • Specialized
translation icon : número racional
  • The students learned that a rational number is any number that can be expressed as the ratio of two integers.
  • approximate them by rational numbers

You can approximate a real number as close as you want with rational numbers, but not with integers.

Autoplay Next

Examples

  • OK, so we want to find a rational number between X&Y.

  • Evidently there are way, way, way more rational numbers than there are integers.

  • And yet the rational numbers are so much smaller than the real numbers.

  • Starts off with the natural numbers and then the rational numbers, the real numbers.

  • So for example, the rational numbers are countable.

  • Whether you're looking at rational numbers, real numbers, complex numbers, or whatever, they form a mathematical structure called a field.

    Blog text (9)
  • You can approximate a real number as close as you want with rational numbers, but not with integers.

  • Talks about the whole numbers, the natural numbers, integers, rational numbers, irrational numbers.

  • Consider a fifth grader who requires primary prevention instruction to learn about whole numbers, secondary prevention to learn about rational numbers, and tertiary prevention to boost reading skills.

    Academic text (2012)
  • A rational number can be written as a fraction, such as 1/2 or 3/4.

Synonyms

fraction
vsrational number
  • Specialized
20 2.6

A number that shows a part of a whole written as one number over another

requires both numbers to be integers not any real numbers
rational
vsrational number
  • Specialized
1 6.8

A number that can be written as a fraction of two whole numbers

is framed mainly as a ratio of two integers rather than an integer
simple fraction
vsrational number
  • Specialized
1 3.4

A number that shows a part of a whole with whole numbers on top and bottom, like 3/4

can also include whole integers expressed as a ratio
common fraction
vsrational number
  • Specialized
2.3

A number written with two whole numbers separated by a line to show part of a whole, like 3/4

is the general numeric concept not tied to written stacked form

Antonyms

irrational number
  • Specialized
1 5.6

A number that cannot be written as a fraction, for example π or √2

Surface Forms

Morphology

rational + number

This is a straightforward adjective + noun composition: 'rational' (expressible as a ratio) modifies 'number', yielding 'a number that can be written as a fraction'. The meaning is directly derived from the constituents and has clear cross-linguistic equivalents, so a learner who knows both words will understand it.

Etymology

Rational number comes from the idea of a ratio, a simple way to compare two whole numbers. Think of sharing a cake into parts and saying 3 out of 4 — a clear 'fraction' — so rational number means a number you can write as one whole number divided by another.