HENKE'S MED-MATH
DOSAGE CALCULATION, PREPARATION
& ADMINISTRATION
10TH EDITION
• AUTHOR(S)SUSAN BUCHHOLZ
TEST BANK
Reference
Ch. 1 — Multiplying Whole Numbers
Stem
A provider orders potassium chloride 20 mEq PO once daily. The
medication is supplied as 10 mEq tablets. The nurse must
prepare a 3-day home supply. How many tablets total should
the nurse dispense for the 3-day supply?
Options
A. 20 tablets
B. 6 tablets
C. 3 tablets
D. 60 tablets
,Correct Answer
B. 6 tablets
Rationales
• Correct (B): Dose = 20 mEq; each tablet = 10 mEq →
tablets per dose = 20 ÷ 10 = 2. For 3 days: 2 × 3 = 6 tablets.
• A: Mistake: multiplying dose by 1 but interpreting as 20
tablets (20 mEq ≠ 20 tablets).
• C: Mistake: took one tablet per dose (under-dosing).
• D: Mistake: multiplying days by tablets and then by 10
(gross overestimation).
Teaching Point
Multiply tablets per dose by number of doses to get total
supply.
Citation
Buchholz, S. (2024). Henke’s Med-Math: Dosage Calculation,
Preparation & Administration (10th ed.). Ch. 1.
2)
Reference
Ch. 1 — Dividing Whole Numbers
Stem
A provider orders digoxin 0.125 mg PO daily. The pharmacy
supplies tablets of 0.25 mg. The nurse must determine how to
,administer the ordered dose using available tablets. What
portion of a 0.25 mg tablet should the nurse give?
Options
A. ½ tablet
B. ¼ tablet
C. 1 tablet
D. 2 tablets
Correct Answer
A. ½ tablet
Rationales
• Correct (A): Ordered dose 0.125 mg ÷ available 0.25
mg/tablet = 0.5 tablet (½ tablet).
• B: ¼ tablet = 0.0625 mg; underdoses by half.
• C: 1 tablet = 0.25 mg; doubles dose — risk of toxicity.
• D: 2 tablets = 0.50 mg; four times ordered dose —
dangerous.
Teaching Point
Use division of ordered dose by available strength to find
fraction of tablet.
Citation
Buchholz, S. (2024). Henke’s Med-Math (10th ed.). Ch. 1.
3)
, Reference
Ch. 1 — Fractions
Stem
A child is prescribed ibuprofen 5 mg/kg per dose. The child
weighs 18 kg. A liquid ibuprofen concentration is 100 mg per 5
mL. Calculate the volume (mL) to administer for one dose.
Options
A. 4.5 mL
B. 9 mL
C. 1.8 mL
D. 10 mL
Correct Answer
A. 4.5 mL
Rationales
• Correct (A): Dose = 5 mg/kg × 18 kg = 90 mg.
Concentration 100 mg per 5 mL → 90 mg corresponds to
(90 ÷ 100) × 5 mL = 0.9 × 5 = 4.5 mL.
• B: 9 mL would deliver 180 mg (double).
• C: 1.8 mL would deliver 36 mg (under-dose).
• D: 10 mL would deliver 200 mg (overdose).
Teaching Point
Convert mg to mL using fraction of concentration:
(desired/available) × volume.
DOSAGE CALCULATION, PREPARATION
& ADMINISTRATION
10TH EDITION
• AUTHOR(S)SUSAN BUCHHOLZ
TEST BANK
Reference
Ch. 1 — Multiplying Whole Numbers
Stem
A provider orders potassium chloride 20 mEq PO once daily. The
medication is supplied as 10 mEq tablets. The nurse must
prepare a 3-day home supply. How many tablets total should
the nurse dispense for the 3-day supply?
Options
A. 20 tablets
B. 6 tablets
C. 3 tablets
D. 60 tablets
,Correct Answer
B. 6 tablets
Rationales
• Correct (B): Dose = 20 mEq; each tablet = 10 mEq →
tablets per dose = 20 ÷ 10 = 2. For 3 days: 2 × 3 = 6 tablets.
• A: Mistake: multiplying dose by 1 but interpreting as 20
tablets (20 mEq ≠ 20 tablets).
• C: Mistake: took one tablet per dose (under-dosing).
• D: Mistake: multiplying days by tablets and then by 10
(gross overestimation).
Teaching Point
Multiply tablets per dose by number of doses to get total
supply.
Citation
Buchholz, S. (2024). Henke’s Med-Math: Dosage Calculation,
Preparation & Administration (10th ed.). Ch. 1.
2)
Reference
Ch. 1 — Dividing Whole Numbers
Stem
A provider orders digoxin 0.125 mg PO daily. The pharmacy
supplies tablets of 0.25 mg. The nurse must determine how to
,administer the ordered dose using available tablets. What
portion of a 0.25 mg tablet should the nurse give?
Options
A. ½ tablet
B. ¼ tablet
C. 1 tablet
D. 2 tablets
Correct Answer
A. ½ tablet
Rationales
• Correct (A): Ordered dose 0.125 mg ÷ available 0.25
mg/tablet = 0.5 tablet (½ tablet).
• B: ¼ tablet = 0.0625 mg; underdoses by half.
• C: 1 tablet = 0.25 mg; doubles dose — risk of toxicity.
• D: 2 tablets = 0.50 mg; four times ordered dose —
dangerous.
Teaching Point
Use division of ordered dose by available strength to find
fraction of tablet.
Citation
Buchholz, S. (2024). Henke’s Med-Math (10th ed.). Ch. 1.
3)
, Reference
Ch. 1 — Fractions
Stem
A child is prescribed ibuprofen 5 mg/kg per dose. The child
weighs 18 kg. A liquid ibuprofen concentration is 100 mg per 5
mL. Calculate the volume (mL) to administer for one dose.
Options
A. 4.5 mL
B. 9 mL
C. 1.8 mL
D. 10 mL
Correct Answer
A. 4.5 mL
Rationales
• Correct (A): Dose = 5 mg/kg × 18 kg = 90 mg.
Concentration 100 mg per 5 mL → 90 mg corresponds to
(90 ÷ 100) × 5 mL = 0.9 × 5 = 4.5 mL.
• B: 9 mL would deliver 180 mg (double).
• C: 1.8 mL would deliver 36 mg (under-dose).
• D: 10 mL would deliver 200 mg (overdose).
Teaching Point
Convert mg to mL using fraction of concentration:
(desired/available) × volume.
