Pharmacy calculations worksheet with answers

A solution is 0.5% w/v. You need 4.5 mg of the drug. Draw up the volume in the syringe: what volume V is that?

Practice exercise (made-up values, not clinical guidance). How many g of sodium chloride are in 100 mL of 3% w/v solution? Find m.

A solution has a ratio strength of 1:1000. You need 0.73 mg. Draw up the volume in the 1 mL syringe: what volume V is that?

Practice exercise (made-up values, not clinical guidance). A vial contains ceftriaxone 2000 mg as a powder. The practice label says to add 19.2 mL of sterile water; the powder adds 0.8 mL to the volume. The prescribed dose is 1200 mg. What volume V do you draw up? Round to one decimal place.

A vial holds 250 mg of powder. You add 1.9 mL of diluent, and the powder adds 0.6 mL of volume. The prescription is 210 mg. Draw up the dose: what volume V do you give?

Practice exercise (made-up values, not clinical guidance). You have 120 g of 10% salicylic acid ointment. How many grams m of 2% salicylic acid ointment must you add to make a 5% ointment? Round to the nearest whole gram.