How to Say and Write Fractions in Spanish

Spanish uses several methods for fractional numbers

student doing a math problem on a chalkboard

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Fractions in Spanish can be stated in several ways depending on the formality of the speech and the size of the number. As always, where there is a choice of which form to use, listening to or reading the fractions in everyday use will help you develop a feel for which form is appropriate.

Halves and Thirds

The special forms la/una mitad and el/un tercio can be used for "half" and "third," respectively. Some examples of usage:

  • Apple redujo a la mitad el precio de su iPhone más barato. (Apple reduced to half the cost of its cheapest iPhone.)
  • El estudio revela que la mitad del software utilizado en la nación es pirateado. (The study shows that half the software used in the nation is pirated.)
  • Una mitad y otra mitad hacen uno. (One half plus another half make one.)
  • Eres mucho más que una mitad de un par. (You are much more than half of a couple.)
  • Predicen la desaparición de dos tercios de los osos polares antes de 2050. (They predict the disappearance of two-thirds of polar bears before 2050.)
  • Perdió un tercio de su valor en menos de dos años. (It lost a third of its value in less than two years.)
  • Los internautas españoles pasan un tercio de su tiempo libre conectados a la red. (Spanish Internet users spend a third of their free time connected to the web.)

Fourths Through Tenths

For fourths through tenths, you can use the masculine form of the ordinal numbers. These forms are cuarto (fourth, quarter), quinto (fifth), sexto (sixth), séptimo, sétimo (seventh), octavo (eighth), noveno (ninth) and décimo (tenth). Some examples:

  • Un cuarto de los anfibios y reptiles europeos está en peligro de extinción. (A quarter of European amphibians and reptiles are in danger of extinction.)
  • La aprobación de la reforma constitucional requerirá la obtención de una mayoría favorable de tres quintos de senadores en una votación final. (The approval of constitutional reform requires the obtaining of a favorable majority of three-fifths of the senators in a final vote.)
  • Dos sextos es igual a un tercio. (Two-sixths is the same as one-third.)
  • Tres séptimos más un séptimo es igual a cuatro séptimos. (Three-sevenths plus one-seventh equals four-sevenths.)
  • El kilómetro es casi igual a cinco octavos de una milla. (A kilometer is about equal to five-eighths of a mile.)
  • El ingreso total sería de ocho novenos del salario mínimo legal. (The total income would be eight-ninths of the minimum legal wage.)
  • Perdió tres décimos de su peso. (He lost three-tenths of his weight.)

Use of Parte

In everyday speech, it is common to express fractions by using the feminine form of the ordinal numbers followed by parte (which means "part" or "portion").

  • La tercera parte de internautas admite usar la misma contraseña para todos sus accesos web. (A third of Internet users admit using the same password for all their accesses to websites.)
  • Más de la cuarta parte de las fuerzas armadas buscan terroristas. (More than a fourth of the armed forces are looking for terrorists.)
  • Se dice que una sexta parte de la humanidad es analfabeta. (It is said that a sixth of humanity is illiterate.)
  • Ella posee siete octavas partes de la casa. (She owns seven-eighths of the house.)_
  • El litro es la centésima parte de un hectolitro. (A liter is a hundredth of a hectoliter.)
  • La pulgada es la duodécima parte del pie y equivale a 2,54 cm. (The inch is 1/12th of a foot and is equivalent to 2.54 centimeters.)

Sometimes the parte is omitted if the context makes it unnecessary

Also, with larger numbers (i.e., smaller fractions), it is not uncommon for the ordinal number to be substituted. So, for example, you may hear doscientas cinco parte for 1/205th.

The -avo Suffix

The suffix of -avo is the rough equivalent of the "-th" (or, sometimes, "-rd") suffix in English and can be used for "eleventh" and beyond. It is attached to the cardinal numbers. Sometimes the stems are shortened; for example, you'll see both veintavo and veinteavo used for one-twentieth. Also, ciento is shortened, so a hundredth is a centavo. The ending of -ésimo is sometimes used instead, as for the thousandths. The use of the -avo suffix is somewhat formal and is less common than the equivalents are in English. Examples:

  • Una garrapatea equivale a un ciento veintiochoavos de redonda. (A semihemidemisemiquaver is equivalent to a 1/128th of a whole note.)
  • El interés mensual es equivalente a un doceavo de la tasa de interés anual. (The monthly interest is equivalent to a twelfth of the annual interest rate.)
  • En ningún caso el crédito diario excederá a un treintavo de los cargos. (In no case will the daily interest exceed a thirtieth of the charges.)
  • El grueso de un vidrio corriente es de dos milésimos de metro. (The thickness of ordinary glass is two-thousandths of a meter.)

Decimals and Percentages

As in English, fractions in Spanish are commonly expressed in percentages and decimals.

The phrase for "percent" is por ciento and phrases using percentages are treated as masculine nouns: El 85 por ciento de los niños españoles se considera feliz. Eighty-five percent of Spanish children are considered happy.

In most of the Spanish-speaking world, commas are used where decimal points are used in English. Thus "2.54" in English becomes 2,54 in Spanish. In Mexico, Puerto Rico and much of Central America, however, the convention used in U.S. English is followed: 2.54.

In speech, numbers with decimals can be expressed digit by digit as in English. Thus you could say dos coma cinco cuatro or dos punto cinco cuatro depending on where you are. (A punto is a period, a coma a comma.)

Key Takeaways

  • Halves and thirds are frequently stated in Spanish using mitad and tercio, respectively.
  • Special words are used for the fourths (cuartos) through the tenths (décimos).
  • For elevenths, twelfths, and beyond, Spanish uses either the suffix -avo or the word parte following the ordinal numbers.
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Erichsen, Gerald. "How to Say and Write Fractions in Spanish." ThoughtCo, Apr. 5, 2023, thoughtco.com/fractions-in-spanish-3079582. Erichsen, Gerald. (2023, April 5). How to Say and Write Fractions in Spanish. Retrieved from https://www.thoughtco.com/fractions-in-spanish-3079582 Erichsen, Gerald. "How to Say and Write Fractions in Spanish." ThoughtCo. https://www.thoughtco.com/fractions-in-spanish-3079582 (accessed March 29, 2024).