Do you want to know how to express fractions? You are in the right place! This lesson will be a milestone in your learning journey. Going through it, you will understand the differences and similarities of fractions between English and languages, along with their number and gender specifications. To simplify, this practical guide will cover these different sections:

the difference between fractions and ordinal numbersthe most common fractionsthe different expressions for themthe suffixes -avo and -imopercentages and decimals using fractions

¡Vamos por partes!Let’s go part by part!

Fractions vs Ordinal Numbers

First things first: fractions are equal parts of a whole. When it comes to math, it is represented with a number called the numerator, that goes on top, and a denominator that goes at the bottom. The numerator tells you how many parts of the whole are taken and the denominator indicates how many parts the whole was divided into. If you ate two parts of a cake that was divided into 7 parts, you ate 2/7th of the cake.

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On the other hand, ordinal numbers designate a number to rank or order parts. It can be a competition (1st place, 2nd place), building floors (3rd floor, 4th floor), locations (5th house, 2nd door, 3rd traffic light) or processes (first, you pour the milk, second, you pour the flour).

In order to express fractions in, cardinal numbers (1, 2, 3) and ordinal numbers (1st, 2nd, 3rd) work together, one right after the other. The cardinal number is used to describe the numerator and the ordinal number is used to describe the denominator. Keep reading to discover how to formulate fractions and what are the most common ones!

Most Common Fractions

Sure, a whole can be divided into a million parts, but it would be very unusual to do it on a cake. While counting to a million in might be useful occasionally, most real-life fractions are small. These little numbers can be helpful when following a recipe, dividing a small area or running a not-so-sophisticated statistic, of children in a classroom for example. Here’s a table that goes from two fractions up to ten, in noun form.

English Fractions
Halfmitad, medio

When to Use Medio, Media or Mitad

Both medio (masculine) and media (feminine) are adjectives that describe “fifty percent of” any given noun. Meanwhile, mitad is a feminine noun. All three words mean “half,” but their usage is dependent on their function in the sentence.

In the following examples, media and medio describe the noun. Because they are adjectives, they do not require an article (le, la).

Tengo media sandía.I have half a watermelon.

Tienes medio melón.You have half a melon.

La mitad is a feminine noun that stands alone. When you divide a whole, like a watermelon or a melon, la mitad can express “the half of” a feminine noun or a masculine noun.

Quiero comer la mitad de la sandía.I want to eat half of the watermelon.

Ella se comió la mitad del pastel.She ate half of the cake.

La mitad de la gente estaba decepcionada.Half of the people were disappointed.

Metí la mitad de los copos de nieve en una bolsa.I put half of the snowflakes in the bag.


Adjective (medio) vs Noun (la mitad)

In the following example, medio estadio works the same way the expression bello estadio does—adjective (medio, bello) + noun (estadio):

Medio estadio estaba gritando.Half the stadium was shouting.

In the following example, la mitad de las personas works the same way the expression la mayoría de las personas does—noun (la mitad, la mayoría) + de + noun (las personas):

La mitad de las personas en el estadio estaban gritando.Half of the people at the stadium were shouting.

Since “half a person” (media persona) doesn’t exist, the expression instead divides the group of people into la mitad.

How to Express Fractions

In order to refer to fractions you need to know a little about its formula in a sentence, its two different expressions, its suffixes, and how to handle numbers and genders. By the end of the lesson you will be an expert on the subject!

Formulating Fractions

Like the introduction says, cardinal and ordinal numbers are needed in order to express fractions. We will use two thirds, 2/5, as an example. But first, a quick refresher on the parts of a fraction:

Dos quintos: 2/5

The number on top (2) is the numerator—in, el numerador.

The number on the bottom (5) is the denominator—in, el denominador.

Numerator: Dos (cardinal number)

Denominator: Quintos (ordinal number)

Numerators other than one make the denominator plural, requiring an -s at the end, just like in English (two fifths). If you are not sure How to Use Numbers in you can go over that lesson before continuing.

When the numerator is one, like one fifth ⅕, use the indefinite article un instead of uno.

Un quintoOne fifth / A fifth

Necesito un quinto de harina.I need a fifth of flour.

Tercio vs Tercera

Tercio and tercera are both terms that translate to “third” in English and refer to fractions of a whole that have been divided into three equal parts.

However, the word tercio is a masculine noun that is only used for fractions:

Un tercio de la población prefiere comida dulce.A third of the population prefers sweet food.

Meanwhile, the word tercera is a femenine adjective that has more than one purpose. You can say:

la tercera vez – the third timela tercera persona – the third partyla tercera en la lista – third on the list

In order to be considered a fraction, tercera must be followed by the word parte:

La tercera parte de la población prefiere comida dulce.

The third part of the population prefers sweet food.

Fractions as Adjectives

Considering the differences between tercio and tercera, we can now move on to fraction expressions in adjective form. While their function in the sentence differs (noun vs. adjective), their meaning is virtually the same. Here are some more fractions in adjective form:

English Adjective
Halfmedio, media
Thirdtercera (parte)
Quartercuarta (parte)
Fifthquinta (parte)
Sixthsexta (parte)
Seventhséptima (parte)
Eighthoctava (parte)
Ninthnovena (parte)
Tenthdécima (parte)

Una mitad del pastel es verde y la otra es morada.One half of the cake is green and the other half is purple.

Mi papá comió la mitad del pie de manzana.My dad ate half of the apple pie.

Me gustaría la tercera parte del pastel.I’d like a third (part) of the cake.

Formula: Fraction + De + Noun

When you use fractions, you can be more specific in your descriptions by using the formula fraction + de + noun

The preposition de undergoes changes depending on the type of noun (or pronoun) that follows it. Take a look:

1. De before possessive pronouns:

La mitad de mi casa.Half my house.

Un tercio de tu vida.A third of your life.

2. Del is a contraction of de and el for masculine nouns:

Un tercio del patio.One third of the patio.

La quinta parte del mundo.A fifth part of the world.

3. De la applies if the noun is feminine:

La mitad de la taza.Half the cup.

Una sexta parte de la cocina.One sixth of the kitchen.

4. De lo que means “of what”:

Un cuarto de lo que me debes.A quarter of what you owe me.

La mitad de lo que necesito.Half of what I need.

La octava parte de lo que gastas.The eighth part of what you spend.

5. De los (masculine) and de las (feminine) refer to plural nouns:

La mitad de los niños.Half the boys.

La séptima parte de las tartas.The seventh part of the tarts.


Sometimes you will need to use multiples that are fractions as well. Two parts of one or 2/1 can be understood as double. Six parts of two is the same as 6/2, the same as 3/1, the same as triple. Here are some examples of the most common multiples in conversation:

English Multiples

The -avo Suffix

So far, you’ve learned about the most common fractions. The list goes from 2 to 10 or from mitad to décimo. Afterwards we went through a quick lesson of fractions as parts using femenine gender. But what happens after that number? That’s where the suffix -avo comes in handy! To express fractions from 11 to 99 you only need to add -avo:

English Fractions

Just like before, if you are in need to include the word partes, remember to change the gender from masculine to feminine by switching the -o at the end of the suffix -avo to -a like this:

La veinteava parte.The twentieth part.

When the number of parts happens to be something as high as 99, it’s easier to just say “one out of ninety-nine,” or “one in ninety-nine” for 1/99:

Uno sobre noventa y nueve.One out of ninety-nine.

Uno entre noventa y nueve.One in ninety-nine.

The -imo suffix

Do you want to know what happens from the number 100 and on? Wow, you are a really thorough researcher! The -imo suffix helps us indicate minimal parts of a whole, which is most commonly used to express percentages.

English fractions

A hundredth part can be translated to 1% or a thousandth to 0.1% to make some expressions easier. In the next section you will learn how to use percentages and decimals in


To express percentages, simply use the cardinal number and add por ciento. For example:

Este producto es 10% (diez por ciento) azúcar.This product is 10% (ten percent) sugar.

20% (veinte por ciento) de la población prefiere clima frío.20% (twenty per cent) of the population prefer cold weather.


Decimals are written and pronounced in two different ways. In Mexico, Puerto Rico, and Central America the most common way of using this math expression is with a period (or “point”), just like in the US:


Cinco punto ocho.Five point eight.

In South America, Spain and the rest of Europe, the comma is preferred over the period and it looks like this:


Cinco coma ocho.

See more: How Many Corn Cobs Per Stalk ? How Many Ears

Five comma eight.

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