Can anyone assist please.

If have a metered exposure of f32 at 1 second, but want to make up the 1 second period out of multiple shorter exposures - say 250 second for example. How do I calculate how many times I must expose at 250 sec to achieve the 1 second period?

I assume there is a simple math process for determining this, but will the mathematical correct number of exposures, give more "actual" exposure to the negative, than the one single exposure of the total time.


Thanks
Peter