The ruling on doubt regarding the number of prostrations after another unit of prayer has passed

Question:
A man doubts the number of prostrations, and he has already moved on to another unit of prayer. What should he do?

Answer:
If he doubts whether he prostrated two times or three, the original assumption is that it was two, and he owes nothing. However, if he doubts whether he prostrated once or twice, he assumes it was one and acts upon certainty by prostrating a second time. If this doubt arises after the unit of prayer has passed and he is in the second unit, the first unit is considered invalid, and the second unit takes its place. He must perform an additional unit to replace the one from which he omitted the prostration, or in which he doubted the prostration he omitted. This is because it is obligatory to perform the pillars completely with certainty. If he prays one unit, and then in the second unit, after bowing or during prostration, he becomes uncertain about the first unit—whether he prostrated twice or once—he assumes it was one with certainty, considers the second unit as a replacement for it, performs another unit, and prostrates for forgetfulness. As for if the doubt occurs after the closing salam, he owes nothing. If the doubt is after the salam, he does not pay attention to it, his prayer is valid, and he does not have to prostrate for forgetfulness or do anything else, because the act of worship has been completed and ended. Yes.

The presenter : May Allah reward you with good.