Educational exam prep, not medical advice. This page teaches what certification exams test. Follow your facility’s policies, your supervising clinician and the manufacturer’s instructions in practice. If you are a patient with a health question, talk to your clinician or see MedlinePlus.
- 1,297 original questions: CNA, PTCB, CCMA
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Days supply
Days supply = quantity dispensed / units used per day (rounded down).
- 1,297 original questions: CNA, PTCB, CCMA
- Timed full-length exams + domain score reports
- 90 days, one-time - emailed to you after purchase
Your course access is emailed to you after purchase. 14-day money-back guarantee. Refund policy
Exam-prep tool for practicing calculations. Not for dispensing decisions.
Practice this: #60 capsules, 1 cap bid -> 60 / 2 = 30 days. Now try 120 mL of a suspension at 5 mL tid (answer: 8 days, since 120 / 15 = 8).
Dilution (C1V1 = C2V2)
Find how much stock solution you need to make a weaker final solution.
- 1,297 original questions: CNA, PTCB, CCMA
- Timed full-length exams + domain score reports
- 90 days, one-time - emailed to you after purchase
Your course access is emailed to you after purchase. 14-day money-back guarantee. Refund policy
Exam-prep tool for practicing calculations. Not for compounding decisions.
Practice this: make 1,000 mL of 2% from 10% stock -> (2 x 1,000) / 10 = 200 mL stock + 800 mL diluent.
Alligation
Mix a higher and a lower strength to reach a desired strength. The desired strength must fall between the two.
- 1,297 original questions: CNA, PTCB, CCMA
- Timed full-length exams + domain score reports
- 90 days, one-time - emailed to you after purchase
Your course access is emailed to you after purchase. 14-day money-back guarantee. Refund policy
Exam-prep tool. If the desired strength is not between the two strengths, the result is not meaningful.
Practice this: 240 g of 1% cream from 2.5% cream and plain base (0%) -> parts 1 : 1.5, so 96 g of 2.5% and 144 g of base.
IV flow rate
mL/hr = volume / hours; gtt/min = (volume x drop factor) / minutes.
- 1,297 original questions: CNA, PTCB, CCMA
- Timed full-length exams + domain score reports
- 90 days, one-time - emailed to you after purchase
Your course access is emailed to you after purchase. 14-day money-back guarantee. Refund policy
Exam-prep tool for practicing calculations. Not for clinical infusion decisions.
Practice this: 500 mL over 4 hours with a 20 gtt/mL set -> 125 mL/hr and (500 x 20) / 240 = 41.7, about 42 gtt/min.
Keep practicing
CNA, PTCB and CCMA prep course - $19
1,297 original practice questions for CNA, PTCB and CCMA, with explanations, timed exams and domain score reports. One-time $19 for 90 days, emailed to you after purchase - no subscription.
Your course access is emailed to you after purchase. 14-day money-back guarantee. Refund policy
Frequently asked questions
How do you calculate days supply for a pharmacy?
Quantity dispensed divided by the amount used per day, rounded down.
What is the C1V1 = C2V2 formula?
Stock concentration x stock volume = final concentration x final volume. Solve for the unknown.
How do you calculate drops per minute?
(Volume in mL x drop factor) / time in minutes.
Sources
- PTCB - PTCE Content Outline effective January 6, 2026 (accessed 2026-09-23)