It is not usually possible to put a number before a noun in Japanese. Counters are used, similar to 'head' in 'two head of cattle'.
One situation when counters are not used, is when someone is counting no particular thing. For example, "please count from one to ten in Japanese might produce":
ichi, ni, san, shi, go, roku, shichi, hachi, ku, juu
juuichi, juuni, juusan, juuyon, juugo, juuroku, juushichi, juuhachi, juuku, nijuu
When they come before counters, shi, shichi and ku are usually replaced by yon, nana and kyuu. This is because shi and ku are homophones of the kanji for death and suffering, respectively. Shichi gets confused with ichi and so is usually replaced by nana.
Here we will regard ichi, ni, san, yon, go, roku, nana, hachi, kyuu, juu as the basic set. When other forms are used, we will indicate them.
Larger numbers are: sanjuu 30, yonjuu 40, gojuu 50, rokujuu 60, nanajuu 70, hachijuu 80, kyuujuu 90
hyaku 'a hundred', sen 'a thousand', ichiman 'ten thousand', juuman 'a hundred thousand', hyakuman 'a million', and senman 'ten million'.
There are some phonetic changes with hyaku and sen: sanbyaku 300, roppyaku 600, happyaku 800, sanzen 3,000, and hassen 8,000.
Beyond that, the words are multiples of four zeros, for example, ichioku 100,000,000, etc. It's easy to lose or gain a zero or two when translating.
Example of a complex number: the year 1982 = sen kyuuhyaku hachijuuuni-nen = Shouwa gojuunana-nen (Showa 57 in the Japanese calendar)