Hi Silvienurse, Here is how I would work your math problem. Yes 60mg = 1 gr. 1 gm = 1000mg, so 0.3 gm is 3 tenths of a gm which should = 300mg. 300mg divided by 60 mg = 5 so 0.3gm = 5gr. 0.3gm = 300 mg 60mg = 1gr 300mg -------X 1 gr = 5gr 60mg I hope this is understandable, and helps you. :imbar mwray1