HENKE'S MED-MATH
DOSAGE CALCULATION, PREPARATION
& ADMINISTRATION
10TH EDITION
• AUTHOR(S)SUSAN BUCHHOLZ
TEST BANK
Reference: Ch. 1 — Multiplying Whole Numbers
Stem: A pediatric patient weighs 18 kg. The provider orders 2
mg/kg of Drug A IV once. Drug A is supplied as 10 mg/mL. How
many mL should the nurse prepare?
A. 36 mL
B. 3.6 mL
C. 1.8 mL
D. 0.36 mL
Correct Answer: B. 3.6 mL
Rationale — Correct (B):
Calculate ordered dose: 18 kg × 2 mg/kg = 36 mg. Convert mg
to mL using concentration: 36 mg ÷ (10 mg/mL) = 3.6 mL. Using
,multiplication first (weight × mg/kg) aligns with straightforward
Henke sequence: compute mg required then convert units.
Rationale — Incorrect:
A. 36 mL — decimal-place error: student used 36 mg as mL
without dividing by 10 mg/mL; would overdose by 10×.
C. 1.8 mL — halved result suggests dividing weight by 2 or
halving dose; underdoses patient.
D. 0.36 mL — off by factor of 10 (moved decimal two places);
dangerous underdose.
Teaching Point: Multiply weight × mg/kg first, then convert mg
→ mL by dividing by concentration.
Citation: Buchholz, S. (2024). Henke’s Med-Math: Dosage
Calculation, Preparation & Administration (10th ed.). Ch. 1.
2
Reference: Ch. 1 — Multiplying Whole Numbers
Stem: An antibiotic vial supplies 500 mg reconstituted to 5 mL.
The order is 250 mg per dose, given q6h. How many mL are
needed to prepare six doses?
A. 12.5 mL
B. 15 mL
C. 30 mL
D. 10 mL
Correct Answer: B. 15 mL
,Rationale — Correct (B):
Dose mL per administration = (250 mg ÷ 500 mg) × 5 mL = 0.5 ×
5 mL = 2.5 mL. For six doses: 2.5 mL × 6 = 15 mL. Multiply per-
dose volume by number of doses; this uses sequential
multiplication consistent with Henke’s approach.
Rationale — Incorrect:
A. 12.5 mL — likely used 2.5 mL × 5 doses instead of 6.
C. 30 mL — doubling error (used 5 mL per dose instead of 2.5
mL).
D. 10 mL — corresponds to 4 doses at 2.5 mL; underprepares
medication.
Teaching Point: Compute per-dose volume, then multiply by
number of doses required.
Citation: Buchholz, S. (2024). Henke’s Med-Math: Dosage
Calculation, Preparation & Administration (10th ed.). Ch. 1.
3
Reference: Ch. 1 — Multiplying Whole Numbers
Stem: A clinic orders 4 tablets of Drug B, each tablet labeled
125 mg. The nurse must prepare these tablets for a patient who
will take all tablets at once. What is the total milligram dose to
document?
A. 125 mg
B. 500 mg
, C. 250 mg
D. 625 mg
Correct Answer: B. 500 mg
Rationale — Correct (B):
Total dose = number of tablets × mg per tablet = 4 × 125 mg =
500 mg. Direct whole-number multiplication is used before
documenting or converting.
Rationale — Incorrect:
A. 125 mg — single tablet only, not total.
C. 250 mg — equivalent to 2 tablets; omitted tablets.
D. 625 mg — 125 × 5; added an extra tablet in error.
Teaching Point: Multiply tablet count × mg per tablet to get
total mg.
Citation: Buchholz, S. (2024). Henke’s Med-Math: Dosage
Calculation, Preparation & Administration (10th ed.). Ch. 1.
4
Reference: Ch. 1 — Dividing Whole Numbers
Stem: A provider orders 100 mg of Drug C orally. Tablets
available are 25 mg each. How many whole tablets should the
nurse give?
A. 4 tablets
B. 3 tablets
DOSAGE CALCULATION, PREPARATION
& ADMINISTRATION
10TH EDITION
• AUTHOR(S)SUSAN BUCHHOLZ
TEST BANK
Reference: Ch. 1 — Multiplying Whole Numbers
Stem: A pediatric patient weighs 18 kg. The provider orders 2
mg/kg of Drug A IV once. Drug A is supplied as 10 mg/mL. How
many mL should the nurse prepare?
A. 36 mL
B. 3.6 mL
C. 1.8 mL
D. 0.36 mL
Correct Answer: B. 3.6 mL
Rationale — Correct (B):
Calculate ordered dose: 18 kg × 2 mg/kg = 36 mg. Convert mg
to mL using concentration: 36 mg ÷ (10 mg/mL) = 3.6 mL. Using
,multiplication first (weight × mg/kg) aligns with straightforward
Henke sequence: compute mg required then convert units.
Rationale — Incorrect:
A. 36 mL — decimal-place error: student used 36 mg as mL
without dividing by 10 mg/mL; would overdose by 10×.
C. 1.8 mL — halved result suggests dividing weight by 2 or
halving dose; underdoses patient.
D. 0.36 mL — off by factor of 10 (moved decimal two places);
dangerous underdose.
Teaching Point: Multiply weight × mg/kg first, then convert mg
→ mL by dividing by concentration.
Citation: Buchholz, S. (2024). Henke’s Med-Math: Dosage
Calculation, Preparation & Administration (10th ed.). Ch. 1.
2
Reference: Ch. 1 — Multiplying Whole Numbers
Stem: An antibiotic vial supplies 500 mg reconstituted to 5 mL.
The order is 250 mg per dose, given q6h. How many mL are
needed to prepare six doses?
A. 12.5 mL
B. 15 mL
C. 30 mL
D. 10 mL
Correct Answer: B. 15 mL
,Rationale — Correct (B):
Dose mL per administration = (250 mg ÷ 500 mg) × 5 mL = 0.5 ×
5 mL = 2.5 mL. For six doses: 2.5 mL × 6 = 15 mL. Multiply per-
dose volume by number of doses; this uses sequential
multiplication consistent with Henke’s approach.
Rationale — Incorrect:
A. 12.5 mL — likely used 2.5 mL × 5 doses instead of 6.
C. 30 mL — doubling error (used 5 mL per dose instead of 2.5
mL).
D. 10 mL — corresponds to 4 doses at 2.5 mL; underprepares
medication.
Teaching Point: Compute per-dose volume, then multiply by
number of doses required.
Citation: Buchholz, S. (2024). Henke’s Med-Math: Dosage
Calculation, Preparation & Administration (10th ed.). Ch. 1.
3
Reference: Ch. 1 — Multiplying Whole Numbers
Stem: A clinic orders 4 tablets of Drug B, each tablet labeled
125 mg. The nurse must prepare these tablets for a patient who
will take all tablets at once. What is the total milligram dose to
document?
A. 125 mg
B. 500 mg
, C. 250 mg
D. 625 mg
Correct Answer: B. 500 mg
Rationale — Correct (B):
Total dose = number of tablets × mg per tablet = 4 × 125 mg =
500 mg. Direct whole-number multiplication is used before
documenting or converting.
Rationale — Incorrect:
A. 125 mg — single tablet only, not total.
C. 250 mg — equivalent to 2 tablets; omitted tablets.
D. 625 mg — 125 × 5; added an extra tablet in error.
Teaching Point: Multiply tablet count × mg per tablet to get
total mg.
Citation: Buchholz, S. (2024). Henke’s Med-Math: Dosage
Calculation, Preparation & Administration (10th ed.). Ch. 1.
4
Reference: Ch. 1 — Dividing Whole Numbers
Stem: A provider orders 100 mg of Drug C orally. Tablets
available are 25 mg each. How many whole tablets should the
nurse give?
A. 4 tablets
B. 3 tablets
