Appendix:Spanish numerals

Cardinal and ordinal numerals

Notes

• The number uno (“one”) apocopates (has its final sound or two removed) to un when used before masculine nouns or other numerals:

un paraguas

un buen techo

treinta y un edificios

cuarenta y un mil dólares

• The full form una is used with feminine nouns, unless the word begins with a stressed a- and cannot also exist as a masculine noun:

veintiuna manzanas

veintiún armas

veintiuna árabes (árabe can mean both "male Arab" and "female Arab" and thus must be disambiguated)

• The number ciento (“hundred”) apocopates to cien before all nouns and before all numbers greater than or equal to mil (“thousand”):

cien años

cien manzanas

cien mil dólares

ciento cincuenta personas

• The adjectives primero and tercero become primer and tercer before masculine singular nouns:

el tercer edificio que he construido

el primer buen conejo

• If a conjunction intervenes between the adjective and the noun, however, there is no shortening:

un tercero y postrero golpe

• The use of a comma or dot to separate thousands varies throughout Latin America and Spain. The Real Academia Española accepts both.
• In writing, the numbers from 0 to 9 are usually written with words; the numbers above 20 are usually written as numerals.
• From 11 onward, ordinal numerals can be replaced with cardinal numerals to mean the same thing:

el decimoséptimo día, el día diecisiete