Numbers can take several forms. Of course there are cardinal (one, two) and ordinal (first, second), just like in English, but there are also several more forms:

• fractional ordinal
• a group of people
• the Nth in a sequence, and
• date in the month.

These formulations also have special forms on the question word (which, how many, etc).

For example:

• négy four
• negyedik fourth
• negyed a fouth (a quarter)
• négyes number four in a sequence
• négyen four (group of people)
• negyedike fourth (of the month)
• negyedikén on the fourth of the month

Note the relation between these.

• Add -odik/edik/ödik to the cardinal to get the ordinal
• Remove the -ik from the ordinal to get the fractional ordinal
• Add -as/es to the cardinal to get the sequential number
• Add -an/en to the cardinal to get the group of people
• Add -a/e to the ordinal to get the day of the month.

• hány? how many?
• hányadik? which (ordinal)?
• hányas? which (of sequence)?
• hányan? which (of group of people)?
• hányadika? which day of the month?
• hányadikán? on which day of the month?

• sok much/many
• sokan many (people)
• kevés little, few
• néhány a few
• néhányan a few people
• kicsi (a) little

Note that these words can take many endings, just like any noun might:

• sokat szeretem I want much
• kicsit fáradt vagyok I am a little tired

• hány óra van? what time is it?
• négy óra van. it's four o'clock
• hányadik emeleten lakik? on which floor does he live?
• négyes busz. number four bus.
• negyedik emeleten. on the fourth floor.
• négyen mentünk négyes busszal, negyed négykor. we four (the four of us) went with (by) the number four bus, at a quarter past three o'clock.
• hányadik tanévben vagyunk? in which school year are we?
• negyedik. the fourth.
• hányadika van ma? which day of the month is today?
• a negyedike. the fourth.
• hányadikán van a születésnapod? on Which day of the month is your birthday?
• a negyedikén. on the fourth.

To me, much of the beauty of this language is in the symmetry and parity. A great example of parity is that an answer much be put into same sense as the question.

If the question is
hányas busszal megy az irodába? with which number bus do you go to the office?

Then the answer must balance this:
az ötvennégyes. the number 54.

Note how the question and aswer here are NOT "which bus?.... 74" but "which number bus?..... number 74."

In every single case, we simply add -n to the -dike the Nth of the month to mean on the Nth of the month.

kilencedikén. On the ninth.

When writing dates, this effect is abbreviated to -an or -en (depending on vowel harmony)

Augusztus 9-én. = Augusztus kilencedikén. on the ninth of August.

When talking about past of present events, egyszer means once or one time.
egyszer gazdag voltam, de nem ma. Once, I was rich, but not today.

When talking about future events, it means one day.
Egyszer, egy szép magyar lányt akarok feleségül venni. One day, I want to marry ("take wife-ly") a beautiful Hungarian girl.