"The friend drinks coffee with sugar."
Translation:Der Freund trinkt Kaffee mit Zucker.
"Whereas most neuter or masculine nouns ending in -chen, -lein, -el, or -er, require no change of the noun in the plural, they end in -n in the dative case."
Why does this not become "Zuckern", then? It's following "mit"... that means it is dative, no?