You cannot. Micrograms per centimetre cubed is a measure of density, with dimensions [ML-3] whereas micrograms is a measure of mass with dimensions [M]. They measure different things and elementary dimensional analyses teaches that you cannot convert between measures with different dimensions.
There are 1000 micrograms in a milligram. You have to divide here to convert. 300ug/1000 is 0.3 milligrams.
There are 0.3 milligrams in 300 micrograms.
0.3 mg = 300 micrograms
There are 1000 micrograms in a milligram. Therefore 10 milligrams is 10,000 micrograms. 300 micrograms is 0.3 milligrams. 10-0.3 is 9.7 milligrams.
There are 0.3 milligrams in 300 nanograms. To convert nanograms to milligrams, divide by 1,000.
To convert micrograms to grams, divide by 1,000,000. So 3.3 micrograms is equal to 0.0000033 grams.
To convert 300 mg to 2000 IU you need to first convert the milligrams to micrograms (1,000 mcg is equal to 1 mg). Next, you need to determine what one IU represents.
300 millimeters is equal to 30 centimeters. To convert millimeters to centimeters, divide by 10 since there are 10 millimeters in one centimeter.
There are 1000 micrograms in a milligram. Therefore 300 micrograms is 0.3 milligrams.
300mg equates to 300,000 micrograms (mcg) *(1000mcg per mg).
There are 1000 micrograms in a milligram. So you need to multiply by 1000 here. 0.3x1000 is 300 micrograms.
Convert to a common unit, then compare! Note that 1 centimeter = 10 millimeters.