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Fractional Numbers

In this lesson, we’ll learn about quantificadores fraccionáriosfractional numbers , which define exact fractions, or parts, of a given thing. Let’s have a look:

List of Portuguese Fractional Numbers

Fractional numbers 1/2 – 1/10 Fractional numbers 1/11 – 1/19 Fractional numbers 1/20 – 1/1000

Fractionals, just like multipliers, are paired with the preposition deof (or its prepositional contraction). You may have noticed that there are multiple ways to say fractional numbers. Let’s review the variations:

Using “Parte”

You’ll notice that a lot of these fractional numerals (apart from meio/metade and terço) correspond to the masculine versions of ordinal numerals: quarto, quinto, sexto, décimo, vigésimo, etc. (This happens in English as well.) But when we want to express smaller and smaller fractions, we commonly use the feminine version of those ordinal numerals with the word partepart . For example:
Um sétimo destes impostos vai para caridade.One seventh of these taxes goes to charity.
But also…
Uma sétima parte destes impostos vai para caridade.A seventh(part) of these taxes goes to charity.
Fractions must agree in number with the amount of parts being counted, as in English. So we could count a single seventh part as um sétimo, but two sevenths would be dois sétimos, three sevenths would be três sétimos, and so on.

Using “Avos”

Avos is a funny little word in Portuguese that is used to signal every equal part a unit is divided into, as long as it’s divided more than ten times. Putting it another way: if we divide a certain something in ten equal parts or fewer, we use fractionals without avo, as in:
Um quinto dos estudantes copia em exames.A fifth of all students cheats during exams.
If we divide it into more than ten equal parts, we can use avos, as in:
Um dezassete avos dos estudantes copia em exames.One seventeenth(part) of all students cheats during exames.
In the previous example, we used avos because we divided our student body into seventeen equal parts. Though avos can technically be used for any division beyond ten equal parts, it’s usually not used for multiples of ten. Example:

  • Less common: Vou dar-te trinta avos da minha herança.I’ll give you a one thirtieth(part) of my inheritance.
  • More common: Vou dar-te uma trigésima parte da minha herança.I’ll give you one thirtieth(part) of my inheritance.
  • More common: Vou dar-te um trigésimo da minha herança.I’ll give you one thirtieth of my inheritance.

Notice that, if we use the ordinal + parte construction, avos is no longer used.
Usamos sempre vinte e seis avos do produto.We always use one twenty-sixth(part) of the product.
Usamos sempre uma vigésima-sexta parte do produto.We always use one twenty-sixth(part) of the product.

Comments

  • not completely clear to me..if I want to say 2/5 ,16/17,35/117 how to say it..like if I am going to put this numbers in any mathematical equation how should I say?also use it any sentence to give example

    • Hello! Fractionals can be tricky indeed! The quick and easy rule is that, up to and including ten parts (X/10), you use cardinal numbers to count the amount of fractions, and ordinary numerals to tell how much of a fraction there is. In the case of 1/10, you’d say “um [1] décimo [10]” – “um” is the cardinal number, and “décimo” is an ordinary number; for 2/5, you’d say “dois[2] quintos[5]”; for 3/6, you’d say “três[3] sextos[6]”, and so on. After ten parts (x/11; x/12…x/100;…x/999) you use all cardinal numbers plus the word “avos”. So 4/60 would be “quatro[4] sessenta[60] avos”, for example; 5/34 would be “cinco[5] trinta e quatro[34] avos”. In Mathematics, after 10 parts, you always use “avos”. Hope that helps!

  • Hello! I just noticed that 14 is spelt quatorze here, while in the introduction to the unit named “Numbers 1”, it’s spelt “catorze”. Just saying.

    • Olá, Anna. Thank you for catching that! Both spellings exist in Portuguese, but in European Portuguese, you (and we) should stick to catorze. In Brazil, both are still in use. I’ve already made the change.

  • My brain has exploded into smithereens on this one! I have a horrible feeling I’m never really going to grasp/remember how to say “one twenty-sixth” etc 🙁

    • This topic can be overwhelming! I think the simplest way to go about it is to only worry about memorizing the fractional numbers in the leftmost and rightmost columns of the chart at the top. Then for any other fractions, like 1/26, just use the regular word for the number and stick “avos” on the end, as in “vinte e seis avos”.

      That way you know the more common fractional forms off the top of your head, but for everything else you only have to remember how to say the number. (You could probably even get by without the rightmost column, unless you use a lot of math in your daily life!)

    • When talking mathematically about fractional numbers such as 1/2, you would say “um meio”, or 3/2 “três meios”.
      In everyday life you could use meio (sing.fem.) or meia (sing.fem.) to refer to “half-something”: half an apple = meia maçã; half a spoon = meia colher; half a dozen = meia dúzia; half a coconut = meio coco.
      When referring to “half of something” you’d use “metade”: “half of an apple” = “metade de uma maçã”, “half of a coconut” = “metade de um coco”.

  • I am so not interested in knowing this and again too much information for a lesson but that’s not a surprise because it happens over and over again and again I skip this lesson!

    • No problem! Fractions are useful for some people, but are definitely not for others. We decided to keep this with the other numbers lessons for organizational purposes, but it’s totally fine to skip this. We encourage you to skip around when something is not relevant. Sorry for the frustration.

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