1.Easy
Practice exercise (made-up values, not clinical guidance). A solution of epinephrine has a ratio strength of 1:10 000. How many milligrams m are in 1 mL?
1:10 0001 mL
m = mg
Pharmacy calculations worksheet with answers
2.Easy
A solution is 1% w/v. You need 31 mg of the drug. Draw up the volume in the syringe: what volume V is that?
1% w/v31 mg
V = mL
3.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 2 000 000 units. What volume V do you draw up? Round to one decimal place.
8.2 mL → 500 000 units/mL2 000 000 units
V = mL
4.Medium
A solution has a ratio strength of 1:10 000. You need 0.2 mg. Draw up the volume in the 10 mL syringe: what volume V is that?
1:10 0000.2 mg
V = mL
5.Hard
Practice exercise (made-up values, not clinical guidance). You must prepare 500 mL of 3% hydrogen peroxide from a 30% stock and purified water. How many mL V of water do you need? Round to the nearest whole mL.
30%0%3%500 mL
V = mL
6.Hard
Practice exercise (made-up values, not clinical guidance). You must prepare 500 mL of 5% sodium chloride by mixing 23% and 3% sodium chloride. How many mL V of the 23% solution do you need? Round to the nearest whole mL.
23%3%5%500 mL
V = mL
Answer key
- 1. m = 0.1 mg
- 2. V = 3.1 mL
- 3. V = 4 mL
- 4. V = 2 mL
- 5. V = 450 mL
- 6. V = 50 mL
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