Spanish speakers use ordinal numbers — those used to express numbers in a series — far less frequently than cardinal numbers, but ordinals still have some very important applications in everyday life. Perhaps when you go to work, you must ask for your floor in an elevator. During a job interview or on a college application, you may have to express where you placed in your class standings.

The following list outlines everything you must remember when using ordinal numbers in Spanish:

• Spanish speakers rarely use ordinal numbers after “10th.” After that, they usually use cardinal numbers in both the spoken and written language:

• el séptimo mes (the seventh month)

• el siglo quince (the 15th century)

• Ordinal numbers must agree in gender (masculine or feminine) with the nouns they modify. You can make ordinal numbers feminine by changing the final -o of the masculine form to -a:

• el cuarto día (the fourth day)

• la cuarta vez (the fourth time)

Primero and tercero drop the final -o before a masculine singular noun:

• el primer muchacho (the first boy)

• el tercer hombre (the third man)

• The Spanish ordinal numbers may be abbreviated. You use the superscript o for masculine nouns and the superscript a for feminine nouns. And you use er only for the abbreviations of primer and tercer:

• primero(a): 1o(a)

• segundo(a): 2o(a)

• tercero(a): 3o(a)

• cuarto(a): 4o(a)

• primer: 1er

• tercer: 3er

• A cardinal number that replaces an ordinal number above 10th is always masculine, because the masculine word número (number) is understood:

• la calle (número) ciento y dos (102nd Street)

• In dates, primero is the only ordinal number you use. All other dates call for the cardinal numbers:

• el primero de mayo (May 1st)

• el doce de enero (January 12th)

• In Spanish, cardinal numbers precede ordinal numbers:

• las dos primeras escenas (the first two scenes)