The first number refers to the amount of narcotic pain reliever in the drug - in this case oxycodone; the second number refers to how much acetaminophen is in it. Acetaminophen is used to boost the strength of the narcotic. The first prescription has about double of amount of narcotic pain reliever in it. (http://www.healthcentral.com/chronic-pain/find-drug-113370-73.html )