HENKE'S MED-MATH
DOSAGE CALCULATION, PREPARATION
& ADMINISTRATION
10TH EDITION
• AUTHOR(S)SUSAN BUCHHOLZ
TEST BANK
Ch. 1 — Multiplying Whole Numbers
Stem: The provider orders acetaminophen 250 mg PO every 8
hours for 24 hours. The medication on the unit is stocked as 250
mg tablets. The patient is a 56-year-old weighing 72 kg. How
many milligrams will the patient receive in 24 hours?
A. 500 mg
B. 750 mg
C. 1,000 mg
D. 125 mg
Correct Answer: B. 750 mg
,Rationale — Correct: There are 24 hours ÷ 8 hours per dose = 3
doses/day. Multiply 3 doses × 250 mg/dose = 750 mg in 24
hours. This uses simple whole-number multiplication per
Henke’s method.
Rationale — A: (500 mg) reflects 2 doses × 250 mg (24 ÷ 8
miscounted as 2). This understates total daily dose and could
under-treat pain.
Rationale — C: (1,000 mg) reflects 4 doses × 250 mg (24 ÷ 8
miscounted as 4). This overstates dose and risks toxicity.
Rationale — D: (125 mg) likely results from halving the tablet
erroneously (250 ÷ 2). That is an inappropriate calculation for
this order.
Teaching point: Calculate number of doses first (24 ÷ interval),
then multiply by dose.
Citation: Buchholz, S. (2024). Henke’s Med-Math: Dosage
Calculation, Preparation & Administration (10th ed.). Ch. 1.
Ch. 1 — Multiplying Whole Numbers
Stem: A provider orders cefuroxime 125 mg PO stat and repeats
the same dose 3 times over 24 hours. Tablets available are 125
mg each. The patient is alert and tolerating oral meds. What is
the total milligram amount administered over the 24-hour
period?
A. 125 mg
B. 250 mg
,C. 375 mg
D. 500 mg
Correct Answer: C. 375 mg
Rationale — Correct: Three doses × 125 mg/dose = 375 mg
total. Perform straightforward multiplication of whole numbers
as taught in Ch. 1.
Rationale — A: (125 mg) treats the single dose only, ignoring
repeated doses.
Rationale — B: (250 mg) reflects 2 doses × 125 mg; miscounting
the number of repeats.
Rationale — D: (500 mg) likely from multiplying 4 × 125 mg; an
extra, incorrect dose.
Teaching point: Multiply the ordered dose by the number of
doses to find total daily amount.
Citation: Buchholz, S. (2024). Henke’s Med-Math: Dosage
Calculation, Preparation & Administration (10th ed.). Ch. 1.
Ch. 1 — Multiplying Whole Numbers
Stem: An IV bolus of 50 mL is ordered to be given hourly for 6
hours. The IV solution is labeled 50 mL per syringe. The nurse
must prepare the total volume to be infused over 6 hours. What
total volume should the nurse prepare?
A. 100 mL
B. 200 mL
, C. 300 mL
D. 400 mL
Correct Answer: C. 300 mL
Rationale — Correct: 50 mL/hour × 6 hours = 300 mL total. Use
whole-number multiplication for hourly rate × time to get total
volume.
Rationale — A: (100 mL) reflects multiplying by 2 instead of 6.
Rationale — B: (200 mL) reflects multiplying by 4 instead of 6.
Rationale — D: (400 mL) reflects multiplying by 8 instead of 6.
Teaching point: Multiply hourly volume by hours to obtain total
infusion volume.
Citation: Buchholz, S. (2024). Henke’s Med-Math: Dosage
Calculation, Preparation & Administration (10th ed.). Ch. 1.
Ch. 1 — Multiplying Whole Numbers
Stem: A prescriber orders 480 units of heparin subcutaneously.
Heparin is supplied as 40 units per mL in the vial on the cart.
Calculate how many milliliters the nurse should draw up.
A. 8.0 mL
B. 10.0 mL
C. 12.0 mL
D. 14.0 mL
Correct Answer: C. 12.0 mL
DOSAGE CALCULATION, PREPARATION
& ADMINISTRATION
10TH EDITION
• AUTHOR(S)SUSAN BUCHHOLZ
TEST BANK
Ch. 1 — Multiplying Whole Numbers
Stem: The provider orders acetaminophen 250 mg PO every 8
hours for 24 hours. The medication on the unit is stocked as 250
mg tablets. The patient is a 56-year-old weighing 72 kg. How
many milligrams will the patient receive in 24 hours?
A. 500 mg
B. 750 mg
C. 1,000 mg
D. 125 mg
Correct Answer: B. 750 mg
,Rationale — Correct: There are 24 hours ÷ 8 hours per dose = 3
doses/day. Multiply 3 doses × 250 mg/dose = 750 mg in 24
hours. This uses simple whole-number multiplication per
Henke’s method.
Rationale — A: (500 mg) reflects 2 doses × 250 mg (24 ÷ 8
miscounted as 2). This understates total daily dose and could
under-treat pain.
Rationale — C: (1,000 mg) reflects 4 doses × 250 mg (24 ÷ 8
miscounted as 4). This overstates dose and risks toxicity.
Rationale — D: (125 mg) likely results from halving the tablet
erroneously (250 ÷ 2). That is an inappropriate calculation for
this order.
Teaching point: Calculate number of doses first (24 ÷ interval),
then multiply by dose.
Citation: Buchholz, S. (2024). Henke’s Med-Math: Dosage
Calculation, Preparation & Administration (10th ed.). Ch. 1.
Ch. 1 — Multiplying Whole Numbers
Stem: A provider orders cefuroxime 125 mg PO stat and repeats
the same dose 3 times over 24 hours. Tablets available are 125
mg each. The patient is alert and tolerating oral meds. What is
the total milligram amount administered over the 24-hour
period?
A. 125 mg
B. 250 mg
,C. 375 mg
D. 500 mg
Correct Answer: C. 375 mg
Rationale — Correct: Three doses × 125 mg/dose = 375 mg
total. Perform straightforward multiplication of whole numbers
as taught in Ch. 1.
Rationale — A: (125 mg) treats the single dose only, ignoring
repeated doses.
Rationale — B: (250 mg) reflects 2 doses × 125 mg; miscounting
the number of repeats.
Rationale — D: (500 mg) likely from multiplying 4 × 125 mg; an
extra, incorrect dose.
Teaching point: Multiply the ordered dose by the number of
doses to find total daily amount.
Citation: Buchholz, S. (2024). Henke’s Med-Math: Dosage
Calculation, Preparation & Administration (10th ed.). Ch. 1.
Ch. 1 — Multiplying Whole Numbers
Stem: An IV bolus of 50 mL is ordered to be given hourly for 6
hours. The IV solution is labeled 50 mL per syringe. The nurse
must prepare the total volume to be infused over 6 hours. What
total volume should the nurse prepare?
A. 100 mL
B. 200 mL
, C. 300 mL
D. 400 mL
Correct Answer: C. 300 mL
Rationale — Correct: 50 mL/hour × 6 hours = 300 mL total. Use
whole-number multiplication for hourly rate × time to get total
volume.
Rationale — A: (100 mL) reflects multiplying by 2 instead of 6.
Rationale — B: (200 mL) reflects multiplying by 4 instead of 6.
Rationale — D: (400 mL) reflects multiplying by 8 instead of 6.
Teaching point: Multiply hourly volume by hours to obtain total
infusion volume.
Citation: Buchholz, S. (2024). Henke’s Med-Math: Dosage
Calculation, Preparation & Administration (10th ed.). Ch. 1.
Ch. 1 — Multiplying Whole Numbers
Stem: A prescriber orders 480 units of heparin subcutaneously.
Heparin is supplied as 40 units per mL in the vial on the cart.
Calculate how many milliliters the nurse should draw up.
A. 8.0 mL
B. 10.0 mL
C. 12.0 mL
D. 14.0 mL
Correct Answer: C. 12.0 mL
