How to Count in Russian
Using Russian for numbers and counting can be tricky if you need to work extensively with numbers, such as in mathematics and accounting. Each Russian number has six forms depending on how it's used! The good news is that most of the time, you'll only need to use the nominative case.
Cases are sets of endings that words take to indicate their function and relationship to other words in the sentence. Russian has 6 cases: nominative case (when it is the subject of the sentence); genitive case (when indicating possession); accusative case (when it is a direct object); dative case (when it is an indirect object); instrumental case (when it assists the carrying out of an action); and prepositional case (when used after some prepositions).
Since most people won't find themselves needing to know all the different forms, we'll focus on just the most commonly used form: the nominative case. You'll probably use the numbers between zero and 9 the most.
But wait! In Russian, when you use numbers, you have to follow a few rules:
The number one followed by a noun: This number changes depending on the gender of the following noun: if masculine, say odin followed by the noun as in odin chyelovyek (ah-DEEN chee-lah-V'EHK) (one man); if feminine, say odna and if the noun is neuter, say odno.
The number two followed by a noun: Change noun to singular. For masculine or neuter nouns, say dva, for feminine nouns, say dvye, as in dva chyelovyeka (dvah chee-lah-V'EH-kuh) (two men) and dvye dyevushki (dv'eh D'EH-voosh-kee) (two girls).
The numbers three and four followed by a noun: Change the noun to singular; however, these numbers don't change according to gender.
The numbers five through nine followed by a noun: Change the noun to plural, but do not change the noun according to gender, as in the phrase pyat' dyevushyek (p'aht' D'EH-voo-shehk) (five girls).
Nouns following numerals 10 through 19 take the genitive plural: