Is fasting six days of Shawwal sufficient for someone who fasted 29 days of Ramadan to attain the meaning of the Hadith, "Whoever fasts Ramadan and follows it with six days of Shawwal," especially if he is certain that Ramadan was 30 days?

If a Muslim fasts twenty-nine days based on the moon sighting in his country, there is nothing wrong with him, and his breaking of the fast is valid, according to the Prophet's (peace be upon him) saying: "Fasting is the day you fast, and breaking the fast is the day you break your fast." The principle is that a Muslim should break his fast and fast with the Muslim community.

Whoever is certain that the sighting of the crescent moon of Shawwal was incorrect must make up the day that was confirmed to be from Ramadan. Fasting six days of Shawwal before making up what was missed from Ramadan fulfills the Sunnah, but he may not receive the full reward mentioned in the hadith: "Whoever fasts Ramadan then follows it with six days of Shawwal..."