1.Easy
Practice exercise (made-up values, not clinical guidance). A solution of potassium permanganate has a ratio strength of 1:5 000. How many milligrams m are in 100 mL?
1:5 000100 mL
m = mg
Pharmacy calculations worksheet with answers
2.Easy
Practice exercise (made-up values, not clinical guidance). How many g of sodium bicarbonate are in 50 mL of 8.4% w/v solution? Find m.
8.4% w/v50 mL
m = g
3.Medium
Practice exercise (made-up values, not clinical guidance). A vial contains ceftriaxone 1000 mg as a powder. The practice label says to add 9.6 mL of sterile water; the powder adds 0.4 mL to the volume. The prescribed dose is 750 mg. What volume V do you draw up? Round to one decimal place.
1000 mg9.6 mL+0.4 mL750 mg
V = mL
4.Medium
Practice exercise (made-up values, not clinical guidance). A vial of penicillin G contains 5 000 000 units. Its practice label gives three strengths (see the table). You add 8.2 mL of diluent. The prescribed dose is 1 500 000 units. What volume V do you draw up? Round to one decimal place.
8.2 mL → 500 000 units/mL1 500 000 units
V = mL
5.Hard
Practice exercise (made-up values, not clinical guidance). You must prepare 500 mL of 4% chlorhexidine from a 20% stock and purified water. How many mL V of water do you need? Round to the nearest whole mL.
20%0%4%500 mL
V = mL
6.Hard
A vial holds 500 mg of powder. You add 3.2 mL of diluent, and the powder adds 0.8 mL of volume. The prescription is 225 mg. Draw up the dose: what volume V do you give?
500 mg3.2 mL + 0.8 mL225 mg
V = mL
Answer key
- 1. m = 20 mg
- 2. m = 4.2 g
- 3. V = 7.5 mL
- 4. V = 3 mL
- 5. V = 400 mL
- 6. V = 1.8 mL
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