Using "Uno", "Un", and "Una" and a generalization of any number with a units digit of one?

Question

To start of, let me clarify what I "know" about "*uno*", "*un*", and "*una*": - *Uno* is used when the object is not mentioned. - *Un* is when the object is mentioned. - *Una* is the feminine form of "*Un*". (Again, please correct me if I'm wrong.) With that said, how would these phrases be translated in Spanish. More importantly if we have a phrase where the amount is a two digit number or higher- except eleven- ending with 1 (i.e. 21, 41, 101), would the word "*uno*" change in certain conditions? Phrases in question: - "En julio hay treinta y un días." translates to ".... thirty-one days." - "Francisco tiene veinte y un años." translates to "... 21 years" (I especially have trouble convincing myself that this is the correct way even though I hear it as "....y uno años." - "Las frutas cuestan cincuenta y un centavos" translates to "....fifty-one cents" (Again, hard to believe, so please clarify).

Answer 1

Dear Wyzant client,

Yes your translation is correct. When you are using the right expression .

Here some other examples

Uno and Ciento

Uno and numbers ending in -uno are shortened to un when they immediately precede a masculine noun. When standing alone (that is, being 100 exactly) ciento is shortened to cien before preceding a noun of either gender; the longer form is used within longer numbers (except when preceding mil).

•            un lápiz (one pencil), • una pluma (one pen)

•            cincuenta y un lápices (51 pencils), •cincuenta y una plumas (51 pens)

•            cien lápices (100 pencils)

•            cien plumas (100 pens)

•            ciento tres lápices (103 pencils)

•            ciento tres plumas (103 pens)

•            cien mil lápices (100,000 pencils)

•            cien mil plumas (100,000 pens)

Gender of Numbers

Some numbers change with gender, most of them don't: When a number ends in –uno ("one"), the form -un is used before masculine nouns, and -una before feminine nouns. The uno form is used only in counting. Accent marks are used where needed to maintain the correct pronunciation. The hundreds portions of numbers change in gender even when other parts of the number intervene before the noun.

•            un lápiz (one pencil), • una puerta (one door)

•            veintiún lápices (21 pencils), • veintiuna puertas (21 doors)

•            doscientos lápices (200 pencils), • doscientas puertas (200 doors)

•            doscientos cuatro lápices (204 pencils), • doscientas cuatro puertas (204 doors)