So my problem is 11600/3 = 3867, but I need it to round down to the nearest 5. How can I set my formula to do this??
This could be (assume A1 contains the number you want to round):
This will always round to the previous multiple of 5 (i.e. rounding down). If your intention is to round to the nearest multiple of 5 it could be:
Just in case, to cover negative numbers