another rakʿah to it, perform the prostration of forgetfulness, and his prayer is thereby complete; the two additional rakʿahs count for him as voluntary.

Whoever becomes uncertain in his prayer—unable to tell whether he has prayed three or four rakʿahs—and this is the first time such doubt has occurred to him, must restart the prayer from the beginning. If doubt assails him frequently, he should proceed on what he deems most likely; but if he has no prevailing assumption, he proceeds on certainty instead.