|Resources Spanish Grammar Spanish Numbers|
Cardinal numbers (1, 2, 3, 4, 5, 6...) may be used as adjectives or pronouns. Numbers in Spanish are always singular. Plural forms of numbers don't exist! Most numbers that end in o do not have genders. Cuatro, cinco, ocho, and ciento refer to either female or male. cinco hombres, cinco mujeres. ocho gallos (roosters), ocho gallinas (hens). Uno and numbers ending in uno, such as veintiuno, have a female gender.
Ordinal numbers (first, second, third, forth, fifth, sixth...) indicate the order in which something occurs. There are forms for just about every number, but most often you will use the forms for the numbers one through ten, just as you would in English. After all, you don't here many people say, "He finished the marathon in 117th place!". Remember, all ordinal numbers have both gender and plurals: segundo, segunda, segundos, segundas, etc. Ordinal numbers are adjectives and agree with the noun modified. The forms "primer" and "tercer" are used only before masculine singular nouns. For feminine nouns, you would use "primera" and "tercera".
In Spanish records, there are two main types of numbers used to express figures and dates. The most prevalent being Arabic numbers - the same numbers used today. These are usually easy to read, but some of them are sometimes confusing because their shape could be similar to other numbers, such as: 1 and 7, and 5 and 9.