Shouldn't we also accept "كيف أعد من خمسة إلى عشرة؟" as an answer?
And i reeeeeeeeeeeeeeally think it is أعدُّ
Maybe أعدَّ because it's hypothetical?
how is that? as in the grammar rule in Arabic?
Because when a verb of this form is placed at the beginning of a sentence, it becomes nominative.