Vocabulary: Numbers

Counting in Russian starts with the basic numbers like most other languages. The numbers from 0 to 10 are ноль, один, два, три, четыре, пять, шесть, семь, восемь, девять, десять.
In Russian, numerical terms must agree with the nouns they describe in gender and case. Unlike adjectives, the numbers one and two are declined, but from three onwards, the numbers stay the same, regardless of case or gender.

The numbers for eleven and twelve are derived from ‘one’ and ‘two’: одиннадцать, двенадцать. From thirteen to nineteen they are formed with suffix “-надцать” added to the number’s root: тринадцать, четырнадцать, etc.
When expressing multiples of ten, similar rules apply: двадцать, тридцать, сорок, пятдесят, up to сто (100).
Where a noun is attached to a number from 21-99, the noun will take the singular if the last digit of the number is 1, and plural if the last digit is 2-4. For example, двадцать один год (21 years), тридцать два года (32 years).

When saying ‘one’ in front of a masculine noun, use один, for feminine nouns use одна, and for neuter nouns use одно. For example, один студент, одна студентка, одно окно.
The number ‘two’ has special cases as well: use два in front of masculine and neuter nouns, and две in front of feminine nouns. For example, два студента, две студентки.

When expressing numbers in hundreds, use the basic numbers along with сто: двести, триста, четыреста, and so on.
The term for thousand is тысяча, which can also be declined in a similar fashion to the number ‘one’. For instance, одна тысяча (one thousand), две тысячи (two thousand).
The noun that follows however, uses the genitive plural form if the number of ‘thousands’ is from 2 to 4, and the genitive singular if the number is 5 or more. For instance, четыре тысячи книг (four thousand books), пять тысяч книги (five thousand books).

Ordinal numbers (first, second, third, etc.) are used when speaking of the order of things. They follow similar rules of agreement in case and gender: первый, второй, третий, четвёртый, and so on.
Just like with cardinal numbers, ordinal numbers from three onwards do not decline with noun gender or case.
For numbers between 10 and 20, the ordinal form ends in “-надцатый”: одиннадцатый, двенадцатый, etc.

Remember, practice makes perfect. Commit these number norms to memory by constant use in example sentences and within context.