recurring decimal

6.5

A number with digits after the point that repeat forever

noun
/rɪˈkɜrɪŋ ˈdɛsɪməl/

: decimal periódico

Every rational number can be expressed as either a terminating or a recurring decimal.

Examples

When you divide 1 by 7, the result is a long recurring decimal.
Can you explain what a recurring decimal is?
0.333... is an example of a recurring decimal because the digit 3 repeats forever.
A recurring decimal can be expressed as a fraction.
In mathematics, 0.3333... is an example of a recurring decimal where the digit 3 repeats forever.
To understand fractions better, we explored how the number 1/3 can be represented as a recurring decimal.
When learning about numbers, she found it interesting that 0.6666... is a recurring decimal with the 6 repeating.

Synonyms

repeating decimal

vsrecurring decimal

Specialized

4.2

A decimal number with a group of digits that goes on forever after the decimal point

has identical meaning but uses a different common name

circulating decimal

vsrecurring decimal

Specialized

7.9

A decimal number with a group of digits that repeats forever

shares the same sense but treats it as point notation rather than fraction

Surface Forms

recurring decimal singular

recurring decimals plural

Morphology

recurring + decimal

Both parts are directly compositional: 'recurring' means repeating and 'decimal' refers to a number with a decimal point, so a B1 learner who knows both words can infer it denotes a decimal number in which digits repeat. The concept is cross-linguistically expressed similarly in many languages, so the underlying logic is transparent despite the technical mathematical phrasing.

Etymology

Recurring decimal paints a simple picture: recurring means 'coming back' and decimal means the numbers after the point, so you can imagine the same digits returning again and again. For example, 0.333... shows 3 'repeats forever', so the phrase means 'a decimal where digits repeat forever'.