To give 2 mg of lorazepam PO, how many tablets will you administer?

Problem:  Give 2 mg of lorazepam PO now.  How many tablets will you administer?

Solution by Dimensional Analysis:

Discussion: From the medication label we know each tablet contains 1 mg of lorazepam, so we can write

Also, even though we didn’t use it this way, notice that it is also factually correct to say there is 1 mg of lorazepam in 1 tablet.

The ordered dose of lorazepam was 2 mg.  Since anything can be multiplied or divided by 1 we can write this in fraction form.