Sorry to be asking what is probably a stupid question, but i recently acquired a Minolta X700 film slr and some ilford fp4 (125 ISO) film and i can't work out how to set the correct iso setting on the camera. The dial seems to double the previous number but has 2 increments between these (25,?,?,50,?,?,100...1600) and my maths, which is pretty bad, is struggling here. Can i actually set this correctly?
My apologies for my stupidity and also thanks in advance.

Matt.