Russian has two words for zero, and they are ноль and нуль. For most purposes they are completely interchangeable and decline like this:

You will most encounter these words is when reading phone numbers out loud. In the US one usually reads phone numbers out loud digit by digit:

In Russia they usually break up a seven-digit number into groups of 3-2-2, and you say ноль only when the zero is the first unit in a group of two or three digits, thus:

(The first zero is pronounced as ноль, and the second zero is understood as part of девяносто.)

In the US most people do not refer to the time of day using the twenty-four hour clock (“military time”) unless they have served in the military or are engaged in precise time-keeping functions, but in Russia all official schedules are posted in twenty-four time, so the phrase «ноль часов ноль минут», which means literally “zero hours zero minutes” and can be translated “oh zero hundred” in military parlance, sounds perfectly normal to an average Russian. You can even hear the phrase in the song «В ноль часов и ноль минут» “At midnight,” which is a cute little tune about how hard it is as a child to stay awake all the way till midnight on New Year's Eve. Click the title of the song just above to hear it. Do listen to it. It's charming.

Numbers... numbers are funny things, and human languages have all sorts of quirks in regards to them. For instance, the Ya̧nomamö tribe in South America has only three number words: one, two, and “more than two.” In Arabic grammar a feminine noun agrees with a masculine number and vice-versa, at least for the numbers three to ten. English has a word for a dozen dozens. Lusatian and Slovene have not only singular and plural noun endings, but also dual. And among the quirks of the Slavic languages is this little gem: Russian has a word that means “one and a half,” and that word is полтора/полторы. It declines like this:

Like the numbers два/две, три, and четыре, this number is followed by the genitive singular of the noun that it quantifies. Sample sentences:

Upon reflection one might wonder how the heck a language comes up with a single word for “one and a half.” After all, a caveman is not going to go out looking for one and a half yaks, and a prehistoric Slav never looked for one and a half wives. So why a number for “one and a half”? The reason is simple: it originally came from two words. The Old Russian word for half was полъ, where the final letter was a spoken vowel. The word for second was вторъ, which in the genitive case was втора. When speaking of quantities, ancient Russians talked about “half of the second” «полъ втора» item, and they assumed the listener knew that if they were talking about half of the second, they of course also meant all of the first item as well. Or if talking about a feminine thing they used вторы, which is the feminine genitive form of second. Eventually the vowels ъ and ь started vanishing from the language, which meant in terms of pronunciation they were left with полвтора and полвторы. Languages have the tendency to simplify consonant clusters, and the в eventually vanished (which is the same reason we pronounce здравствуй as [zdrastvuy] not [zdravstvuy].

¹ ГАЗ = Горьковский автомобильный завод = the Gorky Automobile Factory.

One of the meanings of the stem пол- in Russian is “one half.” The place we most commonly see it is in phrases like “It is half past one” (see details) or “I was there at half past one” (see details), but it can combine with other nouns as well that have nothing to do with clock time. The second noun shows up in the genitive singular form to make a single new word:

There is a quirk of spelling in regards to words that start with this stem. If the second part of the word starts with a vowel or with л, then you are supposed to write it with a hyphen:

Likewise you should use a hyphen if the second word is a proper name:

Otherwise the words are not hyphenated:

Words starting with пол- are most often found in the nominative and accusative cases, and in literary Russian the accusative of these words always copies the nominative. You usually don't have to worry about the other cases. Actually, a really good student of Russian will immediately ask, “But how would a Russian deal with those words in the other cases?” The answer is “inconsistently.” The rules of proper writing say one thing; conversational Russian often produces other forms. As a beginner it's best to stick with using them only in the nominative and accusative. If you have to talk about half of something in any other case, substitute the word половина instead.

One of the Russian words for half is половина. It is perfectly regular in declension. Sample sentences:

The most common word for one in Russian is один in its various forms. Morphologically it is an adjective, which means it occurs in masculine, feminine, neuter, and plural forms in all six cases:

Since один is an adjective, it has to agree with its noun in gender:

Why would you need the plural of the number one? You may encounter the plural of один when specifying that you have one item that is pluralia tantum. Plurale tantum are nouns that only occur in the plural. In English we have a few nouns like that, such as pants. You don't say “Hand me the pant” even if you mean just one item of clothing. Instead you say “Hand me the pants.” In Russian the words брюки pants and часы “a watch” only occur in the plural, so if you want to specify one pair of pants or one watch, you theoretically can use the plural of один:

Alas, the Russian number system is not entirely stable, and occasionally you might find an odd bird who objects to using одни with these words. The issue of how to combine numbers with plurale tantum is quite complex, so for the moment trust me that the Russians often say it this way.