Fractions
Introduction
We use fractions (los números fraccionarios or fracciones) to refer to parts of a whole. We use fractions in mathematics as well as in everyday contexts such as recipes (½ litro de agua).
How to write fractions in Spanish
Fraction | Noun | Adjective |
---|---|---|
1/2 | mitad or medio | medio, media |
1/3 | tercio | tercera (parte) |
1/4 | cuarto | cuarta (parte) |
1/5 | quinto | quinta (parte) |
1/6 | sexto | sexta (parte) |
1/7 | séptimo | séptima (parte) |
1/8 | octavo | octava (parte) |
1/9 | noveno | novena (parte) |
1/10 | décimo or décima | décima (parte) |
1/11 | onceavo or undécimo | onceava or undécima (parte) |
1/12 | doceavo or duodécimo | doceava or duodécima (parte) |
1/13 | treceavo | treceava (parte) |
1/14 | catorceavo | catorceava (parte) |
1/20 | veinteavo or vigésimo | veinteava or vigésima(parte) |
1/22 | veintidosavo | veintidosava or vigésimo segunda (parte) |
1/30 | treintavo or trigésimo | treintava or trigésima (parte) |
1/40 | cuarentavo or cuadragésimo | cuarentava or cuadragésima (parte) |
1/50 | cincuentavo or quincuagésimo | cincuentuava or quincuagésima (parte) |
1/55 | cincuentaicincoavo | cincuentaicincoava or quincuagésimo quinta (parte) |
1/60 | sesentavo or sexagésimo | sesentava or sexagésima (parte) |
1/70 | setentavo or septuagésimo | setentava or septuagésima (parte) |
1/80 | ochentavo or octogésimo | ochentava or octogésima (parte) |
1/90 | noventavo or nonagésimo | noventava or nonagésima (parte) |
1/100 | centésimo or centésima | centésima (parte) |
1/105 | cientocincoavo | cientociencoava (parte) |
1/1.000 | milésimo or milésima | milésima (parte) |
1/10.000 | diezmilésimo or diezmilésima | diezmilésima (parte) |
1/100.000 | cienmilésimo or cienmilésima | cienmilésima (parte) |
1/1.000.000 | millonésimo or millonésima | millonésima (parte) |
1/2.000.000 | dosmillonésimo or dosmillonésima | dosmillonésima (parte) |
Things to know about Spanish fractions
Spanish fractions are similar to English fractions: we read the numerator as a cardinal number and the denominator as an ordinal number. The denominator is plural if the numerator is higher than 1.
- Examples:
- 1/4 → un cuarto
- 3/4 → tres cuartos
Exceptions
mitad or medio (½)
The word medio is used in the same way as an adjective. It agrees with the gender and number of the noun it describes.
- Examples:
- medio litro de aguahalf litre of water
- media docena de huevoshalf dozen eggs
The word mitad is usually followed by the preposition de + noun.
- Example:
- la mitad de un préstamothe half of the loan
- mitad de huevos (informal: it goes without saying that it’s a dozen)
Denominators from 3 to 10
Fractions whose denominators include the numbers 3 to 10 are expressed as ordinal numbers. If the number is more than 1, the denominator is plural.
- Examples:
- 1/3 → un tercio
- 4/6 → cuatro sextos
Denominators from 11
From the number 11 denominators are read as cardinal numbers with the ending –avo(s).
- Example:
- 1/11 → un onceavo
If the denominator is a cardinal number made up of two or more words, we write them as one word. The preposition y becomes an i. In the event that two vowels appear one after another, we only write one.
- Examples:
- 9/99 → nueve noventainueveavos
- 1/30 → un treintavo (not:
un treintaavo) - 5/108 → cinco cientochoavos (not:
cinco cientoochovaos)
For multiples of ten in the tens (20, 30, 40, …), we can also use ordinal numbers.
- Example:
- 1/40 → un cuadragésimo o un cuarentavo
However, we don’t typically use the –avo ending as an adjective.
- Examples:
- una vigésima parte de la población (common)a twentieth of the population
- una veinteava parte de la población (less common)
For multiples of ten in the hundreds, thousands, hundred thousands etc. we always use ordinal numbers.
- Example:
- 1/20,000 → un veintemilésimo
Info
When using fractions in the hundreds, thousands, hundred thousands etc. as nouns, Spain uses the feminine form of the noun while some countries in Latin America also use the masculine form.
- Examples:
- la diferencia de una décima de milímetro (Spain)the difference of one tenth of a millimetre
- la diferencia de un décimo de milímetro (Latin America)