The answer depends on what is being measured: the mass of the mixture that makes up the tablet or the mass of the active ingredient. It also depends on the mass of the tablet itself.
One half of a 0.1mg tablet is 0.05mg
Each Alka-Seltzer tablet contains 325 mg of aspirin.
100mg.
Regular Motrin contains 200 mg of ibuprofen.
3,333.33
175 mg
3
60 mg = 0.06 g
1 MG
You cannot get an even number of pills when using 750 mg tablets in substitute of a 5000 mg tablet. You could make 6 tablets using the 750 mg but would leave 500 mg remaining which you could not make using a 750 mg tablet.
It is mg.
None. Except that the amount of the active ingredient in the 500 mg tablet may be more accurate.