"What is the first number?"
Translation:Ποιος είναι ο πρώτος αριθμός;
It would though! Είναι τεσσάρι, οχτάρι, κάτι άλλο; ;) But only in such a context, which would understandably be out of scope for these lessons. :)
That's what I was thinking a couple of minutes ago, but then I realized that it's kind of a farfetched alternative for duo lessons xP ^.^