There is a rule of thumb on how to build the Greek numerals from 21 onwards: You basically count, like you would count in English. You first name the multiple of ten (e.g.: „είκοσι“ – twenty). Then you add the next number (e.g.: „δύο“ – two). So, if you want to translate "twenty two" into Greek, it would be: „είκοσι δύο“.
Let's learn how to count up to one hundred:
The following numerals between 20 and one hundred inflect: 21, 23, 24 31, 33, 34 41, 43, 44 51, 53, 54 61, 63, 64 71, 73, 74 81, 83, 84 91, 93, 94
Please take a look at the chapter that teaches you the basic rules of the inflection of Greek numerals.
If you are counting in Greek - without referring to a noun - you always use the neuter form of the numeral. If you use a numeral in the context of a sentence, the numeral adopts to its referring noun in number and gender.
Please, move on to the next chapter with an overview of the Greek numerals from 101 onwards.