1.Easy
Practice exercise (made-up values, not clinical guidance). 10 g of glycerin is dissolved in water to a total volume of 100 mL. What is the percentage strength p (% w/v)?
10 g100 mL
p = %
Pharmacy calculations worksheet with answers
2.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 5 mL?
1:10 0005 mL
m = mg
3.Medium
A solution has a ratio strength of 1:1000. You need 0.25 mg. Draw up the volume in the 1 mL syringe: what volume V is that?
1:10000.25 mg
V = mL
4.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 500 mg. What volume V do you draw up? Round to one decimal place.
1000 mg9.6 mL+0.4 mL500 mg
V = mL
5.Hard
Practice exercise (made-up values, not clinical guidance). You must prepare 200 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%200 mL
V = mL
6.Hard
A vial holds 1000 mg of powder. You add 4.5 mL of diluent, and the powder adds 0.5 mL of volume. The prescription is 760 mg. Draw up the dose: what volume V do you give?
1000 mg4.5 mL + 0.5 mL760 mg
V = mL
Answer key
- 1. p = 10 %
- 2. m = 0.5 mg
- 3. V = 0.25 mL
- 4. V = 5 mL
- 5. V = 20 mL
- 6. V = 3.8 mL
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