When converting from grains to milligrams, how many milligrams correspond to 2 grains?

To convert grains to milligrams, it's essential to know the conversion factor, which is that 1 grain is equal to approximately 64.8 milligrams. Thus, to convert grains to milligrams, you multiply the number of grains by this factor.

For 2 grains, the calculation would be:

2 grains × 64.8 mg/grain = 129.6 mg.

Since 129.6 mg rounds to 130 mg and not 120 mg, the answer of 120 mg does not accurately represent the conversion. The correct interpretation requires calculating using the factor provided, demonstrating the process of unit conversion clearly and resulting in a value that aligns with standard pharmacological measurements.