A person does not know whether or not he has missed a fast, can he fast intending what he owes

Miscellaneous Issues Regarding Intention

To Fast What We Owe

 A person does not know whether or not he has missed a fast, can he fast intending what he owes/what is required [mā fī al-dhimmah]; i.e. intend qaḍā’ fast if any; otherwise to be considered as a mustaḥabb fast?

A: Yes, he may intend to fast like that.