Some languages also consider different numbers in different way. I have one ball, two balls, and zero balls. Zero might not be plural like in English. Also, some language have a dual distinction that changes thing when there are two of something (not just singular and plural, but singular, dual, and plural).
In Russian, numbers ending in one are singular, except for eleven which is plural.
It’s even more complicated with two plural declensions except for all numbers in 10-20 range having second form
0 мячей
1 мяч
2 мяча, 3 мяча, 4 мяча
5 мячей, 6 мячей, 7 мячей, 8 мячей, 9 мячей, 10 мячей,
11 мячей, 12 мячей, 13 мячей, 14 мячей, 15 мячей, 16 мячей, 17 мячей, 18 мячей, 19 мячей, 20 мячей
21 мяч
22 мяча, 23 мяча, 24 мяча,
25 мячей, 26 мячей, 27 мячей, 28 мячей, 29 мячей, 30 мячей,
… the rest goes the same as 0-10/20-30…
