"The boy would like ten cookies."
Translation:Puer decem crustula velit.
It's [2nd] declension neuter crustulum, -i. crustula, -ae would have an accusative plural in -as, and would be 1st declension. Confusingly enough, [2nd] declension neuter plural nouns [like ilia - flank] move into the first declension all the time in late Latin. [Edited because I stupidly said 3rd declension (i.e. rex, regis etc.) when I meant 2nd. (i.e. servus, serui, etc.)]
Gratias tibi ago!