Neutral Number Suffixes and Other Examples of Counters
Other counters exist as well, such as -kai for counting stairs or floors in a building.
Ichi-kai, ni-kai, san-kai
-Sai would be the counter used to count your age, with the exception of the irregular 20 years of age, called hatachi. This could be because turning 20 is a special birthday, regarding as the coming of age for young Japanese becoming adults.
Issai, ni-sai, san-san, …..hatachi (20)
A more neutral suffix for counting would be –tsu. If you are not sure which to use, this one will be more widely understood by the Japanese listener. Adding this suffix to numbers is a little tricky because the first several numbers will take irregular form.
Finally, when using ordinal numbers in Japanese we come to a suffix that is easy to use. Simply add –ban, to the end of a number and you will have its ordinal equivalent.
First = ichiban
Second = niban
Third = sanban
This rule has very little variance and can safely be used up the number line.