Question:

dear brothers, i have missed a few fasts this ramadan and I want to make it up. But I don't exactly remember which day of ramadan was it. For example, I remember I have missed 3 fasts, but whether they were the 4th of ramzan or 14th of ramzan or 21 of ramzan etc, I do not remember. So my question is when i make them up do i just normally make them up thinking that I have missed 3 fasts in total or is it necessary/obligatory/condition to remember the exact date when the fasts were missed?

Fatwa:

All perfect praise be to Allah, The Lord of the Worlds. I testify that there is none worthy of worship except Allah, and that Muhammad, sallallaahu 'alayhi wa sallam, is His slave and Messenger.

It is not necessary for whoever breaks the fast to remember or intend to make up for a particular day –the 4th or the 5th or else –of Ramadan; rather, he should make up the days with the intention that they are from Ramadan because we are not aware of any religious evidence of this condition, and no scholar has ever mentioned this condition.
However, if you broke the fast without any sound reason, then you are obliged to repent. If you also had intercourse with your wife during the day of Ramadan, it is an obligation to expiate for it as well [in addition to making up the fast] as explained in Fatwa 84189.

Allah Knows best.