"We have small gloves."
Translation:Nous avons de petits gants.
Because of the adjective. When you have a plural noun preceded by an adjective, "des" changes to "de". Note that this only applies when the adjective is before the noun, not if it's after.
When a BANGS adjectives directly modifies a noun, it always comes before the noun it modifies...always! Compare the following:
- un petit gant = a small glove
- de petits gants = small gloves
- les gants sont petits = the gloves are small