ANSWER:

If you immediately remember it or within the span of a minute or two, standup and offer what was missing and then offer 2 prostrations of forgetfulness after the salam and then offer another salam 

But if it is longer than this, repeat the prayer.

QUESTION: What to if i came late for salah and missed one rakah and said salam with imam.and after a short time (like 1-5 minutes) i remember that i missed 1 rakah. What to do now?

Prayer |