Newbie question - Des pantalons? Or des pantalon?

[unkempt echo]

Hello, french newbie here.

When we're talking about multiple trousers, do we add an 's' to the end of "pantalon" or not?

So...
Des pantalons?
Des pantalon?

Same thing with shorts, do we add?:

Des shorts?
Des short?

[sleek knot]

Keep in mind that the plural of the noun and the definite article in the partitive always agree to each other

du (de + le) lait (singular masc)
de la limonade (singular fem)
des (de + les) citrons (plural masc)
des (de + les) pommes (plural fem)

now, which is singular and which is plural depends whether or not an object is countable which depends on whether you can, well, count
-> you can count apples (une pomme, deux pommes, trois pommes)
-> you can't count milk (un lait, deux laits??)

Since « pantalon, short » are both countable, they'll take the plural