The number of Daleks involved in the Time War has never been revealed. According to the "War Doctor" in "The Day of the Doctor", there were "a billion billion Daleks" attacking Gallifrey at the end of the war. We don't know if that was meant to be an actual count or just a way of saying "a very large number". In "Dalek", the Ninth Doctor spoke of "ten million ships" &, in "The Parting of the Ways", he gave the population of one ship as being 200 Daleks. That would give a total of 2 billion Daleks.
Apart from this uncertainty about the number at the end of the war, we also lack information about how many Daleks had been destroyed during the course of the war. We can't, therefore, even estimate the total number involved.