Complete your prayer on the basis of what you're sure of .Prostrate twice while sitting after completing your prayer .

This hadith teaches us that if we are uncertain about how many rak'ahs we have prayed in our salat, we should complete our prayer on the basis of what we are sure of. After completing the prayer, it is recommended to prostrate twice while sitting in order to make the number of rak'ahs even. This will also annoy and humiliate shaitan. By making our prayers even-numbered, it shows that we are taking extra care in fulfilling our religious obligations and being mindful of Allah's commands. It also serves as a reminder for us to be more conscious when praying so that there is no doubt or confusion about how many rak'ahs were performed.