Fractions are just funky when dividing. Dividing by 0.5 is the same multiplying by 2.
Your analogy is really close, but backwards is all. If you have a quarter of an apple. In order to get half a whole apple, you need another quarter. Two quarters make a half, so dividing a quarter by 0.5 gives you 2 quarters. Dividing a quarter by 2 gives you 0.5 of the original quarter which is your 1/8th