According to my grammar sheet, a word like "young" has the comparative/superlative forms of: "jung, jünger, am jüngsten" = "young, younger, youngest." But the "-en" we have here on "größten" is due to the plurality of our subject, while the "t" is due to "größten" being in the superlative form, right?
I wonder why my sheet has "-en" attached to the superlative form by default. Also, what's with the "am" that's supposedly attached to the superlative? It's not in this sentence.