What is the method for making up missed prayers and fasts when their number is unknown, and is it permissible for them to have multiple intentions so that they become supererogatory acts if they exceed the missed ones, while observing the order in making up the prayers?

One must hasten to sincere repentance for neglecting one's duties towards Allah, such as prayer, fasting, and other sins, while maintaining a good opinion of Allah and not despairing of His mercy. For the one who repents from a sin is like one who has no sin. As for someone who has missed many prayers or fasts and does not know their exact number, it is obligatory for them to make them up, exercising caution in estimating their number. Arranging many missed prayers is not obligatory according to some scholars. It is permissible to fast Mondays and Thursdays with the intention of making up missed fasts and observing voluntary fasts.