How can the missed days of Ramadan fasting and the days of fasting related to oaths, whose numbers have become mixed, be estimated in order to perform the obligatory expiation?

The expiation for breaking an oath begins with feeding ten poor persons, or clothing them, or freeing a slave. Fasting is not sufficient unless one is unable to do these three. If fasting is permissible due to inability, and you do not know the number of days for both making up Ramadan fasts and the expiation for breaking an oath, then you must investigate and estimate the number of days for each, because it is necessary to specify the intention for every obligatory fast. If you cannot distinguish between them, it is sufficient for you to fast them with the intention of an obligatory fast due to necessity. As for the expiation for delaying the making up of Ramadan fasts until the entry of another Ramadan without a valid excuse, it is feeding one poor person for each day delayed.