Arithmetical Calculations in Italian
Don't panic, I don't want to teach you arithmetics! Instead, I'd like to help you learn how to talk about some of the easy arithmetical operations that apply in our daily life. Arithmetics is the oldest and simplest branch of mathematics, used by almost everyone. It is practiced daily by all for purposes as simple as counting objects to more advanced business and scientific calculations.
For your time in Italy, it would be helpful to learn how to do some simple operations in Italian. Such as:

Quanto fa sei più uno? = How much/What is six plus one? 6+1 = 7
Sei più uno fa/è uguale a sette = Six plus one is seven

Quanto fa sette meno uno? = How much/What is seven minus one? 71 = 6
Sette meno uno fa/ è uguale a sei = Seven minus one is six.

Quanto fa cinque per quattro? = How much/What is five times four? 5x4 = 20
Cinque per quattro fa/ è uguale a venti = Five times four is twenty.
 Quanto fa sessanta diviso tre? = How much/What is sixty divided by three? 60:3 = 20
Sessanta diviso tre fa/è uguale a venti = Sixty divided by three is twenty.
 Sette diviso tre fa/è uguale a due con il resto di uno. 7:3=2
Seven divided by three is two and one over two (remainder one).
Fractions  Frazioni
In Italian fractions work as in English: the first number is a cardinal number, the second one is ordinal.
un mezzo ½ a half
un terzo 1/3 a third
tre quinti 3/5 three fifths
cinque mezzi 5/2 five over two
quattro mezzi 4/2 four halves
Some examples of how fractions are used in daily speech:
Ho già letto due terzi del libro = I have already read two thirds of the book.
Ne ha bevuto solo metà = He's only drunk half of it.
In Italian when a fraction indicates a quantity the noun to which it refers is preceded by the preposition DI:
due quinti di olio = two fitfths of oil
un quarto di litro = one fourth of a litre
When the numbered object is feminine, ordinal numbers always have the masculine form:
un quarto di dolce = one fourth of cake
vorrei un quarto della torta = I would like one fourth of the cake
tre quinti di farina = three fifths of flour
tre quinti di questa farina = three fifths of this flour
Sometimes we say things like: "I would like a dozen roses (12 roses)" or "We'll be about twenty people at dinner." When discussing rough quantities in Italian here as some useful words and phrases:

una decina = about ten

una ventina = about twenty

una trentina = about thirty

una quarantina = about forty
Alla conferenza c'erano una ventina di uomini = At the conference there was about twenty men.
Quella donna è sulla trentina = That woman is about thirty years old.
Sarò lì tra una quarantina di minuti = I'll be there in about forty minutes.

un centinaio = about one hundred

centinaia = hundreds

un migliaio = about one thousand

migliaia = thousands
Centinaia di feriti = hundreds of wounded
Un centinaio di persone = about a hundred people
Cento penne = one hundred pens
Un centinaio di penne = about one hundred pens
We can also express rough quantities with the word "paio" (pair):
Entro un paio di settimane saremo a Parigi = within a couple of weeks we will be in Paris
Vorrei darti un paio di consigli = I would like to give you a couple of tips
Ho comprato due paia di scarpe = I bought two pairs of shoes
Cinque paia di pantaloni = five pairs of trousers
Ratios / Proporzioni
a sta a b come c sta a x a:b = c:x a is to b as c is to x
Raising to a Power / Potenze
due alla seconda (potenza) / due al quadrato = two to the power of two / two squared
due alla terza / due al cubo = two to the power of three / two cubed
elevare alla quinta = to raise to the power of five
elevare all'ennesima potenza = to raise x to the power of n
Decimal Fractions / Decimali
tre virgola dieci = 3,10 = 3.10 = three point ten
zero virgola zero cinque = 0,05 = 0.05 = zero point zero five
zero virgola zero uno = 0,01 = 0.01 = zero point zero one
due virgola tre periodico = 2,3333.... = two point three recurring
Percentages / Percentuali
A percentage is a way to express a number as a fraction of a whole. For example:
dieci per cento = 10% = ten per cent
cinque virgola cinque per cento = 5,5% = 5.5% = five point five per cent
Il 20% dei lavoratori ha più di 40 anni = Twenty percent of the workers are over 40.
L'offerta è aumentata del 10% = The offer has risen by 10%.
By Elisa Bressan