Hazrat Ibn Umar (may Allah be pleased with them both) said: If I do not know how many units of prayer I have performed, I will repeat the prayer.

Hazrat Ibn Umar (may Allah be pleased with them both), regarding the person who does not remember whether he has prayed three rak‘ahs or four, says that he should repeat the prayer so that he may remember.

Hazrat Sha'bi and Hazrat Sa'id bin Jubair state that if a person finishes the prayer and does not know whether he has prayed an odd or even number of units, then he should repeat the prayer.

4488 - (W) (1) From Ayyub, from Sa'id ibn Jubayr, they said: If he prays and then leaves but does not know how many (rak'ahs) he prayed, whether even or odd, then let him repeat it.

It is narrated similarly through another chain.

Hazrat Mansur says that I asked Hazrat Saeed bin Jubair about a person who has doubt in prayer. He said, if this happens to me in obligatory prayer, I will repeat the prayer.

Hazrat Abu Majliz says that while stoning the Jamarat, I could not remember how many pebbles I had thrown. So I asked Hazrat Ibn Umar (may Allah be pleased with them) about this, but he did not give me any answer. Meanwhile, Hazrat Ibn al-Hanafiyyah passed by; I asked him, and he said, "O servant of Allah! Repeat the stoning. In our view, nothing is greater than prayer; when any of us forgets in prayer, he repeats it." I mentioned this to Hazrat Ibn Umar (may Allah be pleased with them), and he said, "They are the Ahl al-Bayt and are more knowledgeable."

Hazrat Ismail bin Abi Khalid says that Hazrat Sha'bi said that he will repeat the prayer. I mentioned this to Hazrat Abu Duhai, so he said that Hazrat Shurayh was also of the opinion that the prayer should be repeated.

4493 - I mentioned it to Abu al-Duha, and he said: (Shurayh) used to say: He should repeat.

Hazrat Tawus says that if, while performing prayer, you do not know how many units you have prayed, then repeat it once. If the same situation occurs again, there is no need to repeat it again.