Counting the Rak`ah when joining the Imam during Ruku`

Q 2: What is the validity of the prayer of people who precede or accompany the Imam in Ruku` (bowing), prostration, and rising to assume the standing position?

A: A Ma'mum (a person being led by an Imam in Prayer) is obliged to follow the Imam in Ruku`, prostration, and rising from both of them. He should not bow, prostrate, or rise until the Imam does so. The Prophet (peace be upon him) commands the Muslims to do so and forbids preceding or accompanying the Imam at the same time. He (peace be upon him) said, The Imam is appointed to be followed, so do not be at variance with him. Recite Takbir when he recites it; bow down when he bows down. When he says, "Allah listens to him who praises Him," say, "O Allah, our Lord, to You be the Praise." And When he (the Imam) prostrates, you should also prostrate... Reported by Al-Bukhari and Muslim. The Ma'mum is commanded to do these movements immediately after the Imam does them. This immediate following is indicated by the sequence of the imperative verbs mentioned in the Hadith. He also says, (Part No. 7; Page No. 316)  Is not he who raises his head before the Imam afraid that Allah may transform his figure (face) into that of a donkey? Reported by Al-Bukhari and Muslim. Whoever bows, prostrates, or rises from Ruku` or prostration before the Imam or at the same time as him while being attentive and fully aware of the ruling on this matter goes against the Prophet (peace be upon him). Besides this, they are subject to punishment and the Salah performed by them is fruitless and Batil (null and void), and should be performed again. This is based on the report narrated by Ibn `Umar and on the view held by Imam Ahmad ibn Hanbal. On the other hand, whoever precedes the Imam out of forgetfulness or ignorance of the ruling on the matter, his Salah is valid. Moreover, an ignorant person should be informed of the ruling and the distracted person should follow his Imam again once he realizes his diversion from following the Imam out of meeting the obligation of following the Imam.May Allah grant us success. May peace and blessings be upon our Prophet Muhammad, his family and his Companions!