Nouns and Articles - Plurals

The rules for making a Spanish singular noun into a plural noun are fairly straightforward - much less complicated than the English rules for plurals. Simply put, if a noun ends in a vowel you add an "s," and if it ends in a consonant, you add an "es."

The other thing that is different from the English is that the article also becomes plural: "the" before a feminine singular noun is "la"; "the" before a masculine singular noun is "el"; the plurals - you guessed it - will end in "s": feminine = "las"; masculine = "los." (You will have to memorize the "el" and "los"):
"el libro" and "los libros" (the book/books)
"la casa" and "las casas" (the house/houses)