HENKE'S MED-MATH
DOSAGE CALCULATION, PREPARATION
& ADMINISTRATION
10TH EDITION
• AUTHOR(S)SUSAN BUCHHOLZ
TEST BANK
Ch. 1 — Arithmetic Needed For Dosage
Multiplying Whole Numbers
1. Stem
A provider orders amoxicillin 500 mg PO every 8 hours for
7 days. The patient will take 3 tablets per dose (each tablet
is 500 mg). How many tablets will the nurse instruct the
patient to obtain for the full 7-day course?
Options
A. 21 tablets
B. 42 tablets
C. 63 tablets
D. 84 tablets
,Correct answer: C. 63 tablets
Rationales
Correct (C): Calculate doses per day = 24 hr ÷ 8 hr = 3
doses/day. Tablets per dose = 3. Total tablets = 3 tablets/dose ×
3 doses/day × 7 days = 63 tablets. This follows sequential
multiplication of whole numbers per Henke’s method.
A (21): Error — multiplied tablets per dose by days only (3 × 7 =
21), omitting doses per day; would underdose the patient.
B (42): Error — likely 2 tablets/dose × 3 doses/day × 7 days or 3
tablets × 14 days; represents a common doubling/halving
mistake.
D (84): Error — likely 4 tablets/dose assumption or 3 tablets × 4
doses/day × 7 days; overestimation risk.
Teaching point: Multiply dose/unit × doses per day × days;
include doses per day.
Citation: Buchholz, S. (2024). Henke’s Med-Math: Dosage
Calculation, Preparation & Administration (10th ed.). Ch. 1.
Ch. 1 — Arithmetic Needed For Dosage
Dividing Whole Numbers
2. Stem
A clinic dispenses 120 tablets of metoprolol. The provider
instructs the patient to take 2 tablets daily. How many days
will this supply last?
,Options
A. 30 days
B. 40 days
C. 50 days
D. 60 days
Correct answer: D. 60 days
Rationales
Correct (D): Days supply = total tablets ÷ tablets per day = 120 ÷
2 = 60 days. Division of whole numbers yields the duration.
A (30): Error — used tablets per dose instead of per day or
halved the result; short supply risk.
B (40): Error — result of incorrect division (120 ÷ 3) or
misreading instructions.
C (50): Error — arithmetic error; overestimates daily usage risk
if used clinically.
Teaching point: Divide total units by daily units to find days
supply.
Citation: Buchholz, S. (2024). Henke’s Med-Math: Dosage
Calculation, Preparation & Administration (10th ed.). Ch. 1.
Ch. 1 — Arithmetic Needed For Dosage
Fractions
3. Stem
A provider orders hydrocortisone ¾ tablet PO daily. The
, pharmacy stocks scored ¼-tablet units. How many quarter-
tablets should the nurse give per dose?
Options
A. 1 quarter-tablet (¼)
B. 2 quarter-tablets (½)
C. 3 quarter-tablets (¾)
D. 4 quarter-tablets (1)
Correct answer: C. 3 quarter-tablets (¾)
Rationales
Correct (C): Number of ¼ tablets = (3/4) ÷ (1/4) = 3. Using
fraction division (invert and multiply) yields three quarter
tablets per dose.
A (¼): Error — treated ¾ as if it were ¼; underdosing risk.
B (½): Error — misconverted ¾ to 1/2; math error.
D (1): Error — rounded up to whole tablet; may increase steroid
exposure and risk side effects.
Teaching point: Divide fractions (ordered dose ÷ unit fraction) to
get number of dose units.
Citation: Buchholz, S. (2024). Henke’s Med-Math: Dosage
Calculation, Preparation & Administration (10th ed.). Ch. 1.
Ch. 1 — Arithmetic Needed For Dosage
Decimals
4. Stem
A provider orders epinephrine 0.25 mg/kg IV for a 70-kg
DOSAGE CALCULATION, PREPARATION
& ADMINISTRATION
10TH EDITION
• AUTHOR(S)SUSAN BUCHHOLZ
TEST BANK
Ch. 1 — Arithmetic Needed For Dosage
Multiplying Whole Numbers
1. Stem
A provider orders amoxicillin 500 mg PO every 8 hours for
7 days. The patient will take 3 tablets per dose (each tablet
is 500 mg). How many tablets will the nurse instruct the
patient to obtain for the full 7-day course?
Options
A. 21 tablets
B. 42 tablets
C. 63 tablets
D. 84 tablets
,Correct answer: C. 63 tablets
Rationales
Correct (C): Calculate doses per day = 24 hr ÷ 8 hr = 3
doses/day. Tablets per dose = 3. Total tablets = 3 tablets/dose ×
3 doses/day × 7 days = 63 tablets. This follows sequential
multiplication of whole numbers per Henke’s method.
A (21): Error — multiplied tablets per dose by days only (3 × 7 =
21), omitting doses per day; would underdose the patient.
B (42): Error — likely 2 tablets/dose × 3 doses/day × 7 days or 3
tablets × 14 days; represents a common doubling/halving
mistake.
D (84): Error — likely 4 tablets/dose assumption or 3 tablets × 4
doses/day × 7 days; overestimation risk.
Teaching point: Multiply dose/unit × doses per day × days;
include doses per day.
Citation: Buchholz, S. (2024). Henke’s Med-Math: Dosage
Calculation, Preparation & Administration (10th ed.). Ch. 1.
Ch. 1 — Arithmetic Needed For Dosage
Dividing Whole Numbers
2. Stem
A clinic dispenses 120 tablets of metoprolol. The provider
instructs the patient to take 2 tablets daily. How many days
will this supply last?
,Options
A. 30 days
B. 40 days
C. 50 days
D. 60 days
Correct answer: D. 60 days
Rationales
Correct (D): Days supply = total tablets ÷ tablets per day = 120 ÷
2 = 60 days. Division of whole numbers yields the duration.
A (30): Error — used tablets per dose instead of per day or
halved the result; short supply risk.
B (40): Error — result of incorrect division (120 ÷ 3) or
misreading instructions.
C (50): Error — arithmetic error; overestimates daily usage risk
if used clinically.
Teaching point: Divide total units by daily units to find days
supply.
Citation: Buchholz, S. (2024). Henke’s Med-Math: Dosage
Calculation, Preparation & Administration (10th ed.). Ch. 1.
Ch. 1 — Arithmetic Needed For Dosage
Fractions
3. Stem
A provider orders hydrocortisone ¾ tablet PO daily. The
, pharmacy stocks scored ¼-tablet units. How many quarter-
tablets should the nurse give per dose?
Options
A. 1 quarter-tablet (¼)
B. 2 quarter-tablets (½)
C. 3 quarter-tablets (¾)
D. 4 quarter-tablets (1)
Correct answer: C. 3 quarter-tablets (¾)
Rationales
Correct (C): Number of ¼ tablets = (3/4) ÷ (1/4) = 3. Using
fraction division (invert and multiply) yields three quarter
tablets per dose.
A (¼): Error — treated ¾ as if it were ¼; underdosing risk.
B (½): Error — misconverted ¾ to 1/2; math error.
D (1): Error — rounded up to whole tablet; may increase steroid
exposure and risk side effects.
Teaching point: Divide fractions (ordered dose ÷ unit fraction) to
get number of dose units.
Citation: Buchholz, S. (2024). Henke’s Med-Math: Dosage
Calculation, Preparation & Administration (10th ed.). Ch. 1.
Ch. 1 — Arithmetic Needed For Dosage
Decimals
4. Stem
A provider orders epinephrine 0.25 mg/kg IV for a 70-kg
