"Twenty-nine comes after twenty-eight."
Translation:Negenentwintig komt na achtentwintig.
1) we are talking about the number, not about the amount of 'x'.
2) In any case, if you want to talk about the amount of 'x', you have to mention the noun it's referring to (negenentwintig koeien.....),
and 3) na= after
Beware of false friends! ;)