He said: {So We cast a veil over their ears in the Cave for a number of years}.
Muhammad said: And 'a number' (adadan) is in the accusative case (mansub) as a verbal noun (masdar); meaning: they are counted by counting.
قَالَ: ﴿فَضَرَبْنَا عَلَى آذَانِهِمْ فِي الْكَهْف سِنِين عددا﴾.
قَالَ مُحَمَّد: و (عددا) مَنْصُوب (ل ١٩٢) عَلَى الْمَصْدَرِ؛ أَيْ: تُعَدُّ عَدًا.