τὸ πλῆθος οὐκ εὐαρίθμητον ἦν → the crowd wasn't easy to count, the crowd was not small, it was not a small crowd
κερδαντέον: ῥημ. ἐπίθ., δεῖ κερδαίνειν, Μ. Ἀντων. 4. 26.
adj. verb. de κερδαίνω.