Henke's Med-Math Dosage-Calculation, Preparation, and Administration, 9th Edition
(Buchholz,
, Henke's Med-Math Dosage-Calculation, Preparation, and Administration, 9th Edition
(Buchholz,
CHAPTER 1: Arithmetic Needed for Dosage.
Each question has a clinical setup, 4 options, ✅ Correct Answer, and a clear rationale.
Methods highlighted including ratio–proportion, formula, and dimensional analysis,
with plenty of fractions/decimals/percentages.
1. A post-op adult is prescribed acetaminophen 650 mg PO q6h PRN. Tablets are
325 mg each. How many tablets should the nurse administer per dose?
A. 1
B. 1.5
C. 2
D. 3
✅ Correct Answer: C
Rationale: 650 mg÷325 mg/tab=2 tabs650 \text{ mg} ÷ 325 \text{ mg/tab} = 2 \text{
tabs}650 mg÷325 mg/tab=2 tabs. Using the formula method: D/H×V=650/325×1=2D/H
× V = 650/325 × 1 = 2D/H×V=650/325×1=2.
Difficulty: Easy
NCLEX Client Needs Category: Physiological Integrity – Pharmacological and
Parenteral Therapies
Keywords: tablets, formula method, decimals
2. A child is prescribed amoxicillin 250 mg PO. The suspension is 400 mg per 5
mL. How many milliliters should be given? (Use an oral syringe; round to the
nearest 0.1 mL.)
A. 2.5 mL
B. 3.1 mL
C. 3.5 mL
D. 4.0 mL
✅ Correct Answer: B
Rationale: Ratio–proportion 400:5=250:x⇒x=(250×5)/400=3.125 mL400:5 = 250:x
\Rightarrow x = (250×5)/400 = 3.125 \text{
mL}400:5=250:x⇒x=(250×5)/400=3.125 mL. Round to 3.1 mL for oral syringe
accuracy.
, Henke's Med-Math Dosage-Calculation, Preparation, and Administration, 9th Edition
(Buchholz,
Difficulty: Moderate
NCLEX Client Needs Category: Physiological Integrity – Pharmacological and
Parenteral Therapies
Keywords: suspension, ratio–proportion, rounding
3. A provider orders a 1% hydrocortisone cream to apply as a 30-g thin layer to a
rash. How many milligrams of drug are in that 30-g dose?
A. 30 mg
B. 300 mg
C. 3,000 mg
D. 0.3 mg
✅ Correct Answer: B
Rationale: 1% w/w = 1 g per 100 g. 0.01×30 g=0.3 g=300 mg0.01 × 30 \text{ g} = 0.3
\text{ g} = 300 \text{ mg}0.01×30 g=0.3 g=300 mg.
Difficulty: Moderate
NCLEX Client Needs Category: Physiological Integrity – Pharmacological and
Parenteral Therapies
Keywords: percent strength, conversions, decimals
4. The order is heparin 7,500 units SQ. The vial reads 5,000 units/mL. What
volume will the nurse draw up?
A. 0.5 mL
B. 1.0 mL
C. 1.5 mL
D. 2.0 mL
✅ Correct Answer: C
Rationale: Dimensional analysis: 7,500 units×1 mL5,000 units=1.5 mL7{,}500\
\text{units} × \frac{1\ \text{mL}}{5{,}000\ \text{units}} = 1.5\
\text{mL}7,500 units×5,000 units1 mL=1.5 mL.
Difficulty: Easy
NCLEX Client Needs Category: Physiological Integrity – Pharmacological and
Parenteral Therapies
Keywords: units/mL, dimensional analysis
, Henke's Med-Math Dosage-Calculation, Preparation, and Administration, 9th Edition
(Buchholz,
5. The patient needs morphine 2 mg IV push. The vial is 10 mg/mL. What volume
should be administered?
A. 0.1 mL
B. 0.2 mL
C. 0.5 mL
D. 1.0 mL
✅ Correct Answer: B
Rationale: Formula: D/H×V=2/10×1=0.2 mLD/H × V = 2/10 × 1 = 0.2 \text{
mL}D/H×V=2/10×1=0.2 mL.
Difficulty: Easy
NCLEX Client Needs Category: Physiological Integrity – Pharmacological and
Parenteral Therapies
Keywords: IV push, formula method
6. A pediatric order is albuterol 0.125 mg/kg nebulized for a 16-kg child. The
solution is 1 mg/0.5 mL. What volume is prepared?
A. 0.5 mL
B. 0.8 mL
C. 1.0 mL
D. 1.5 mL
✅ Correct Answer: C
Rationale: Dose =0.125×16=2.0 mg= 0.125×16 = 2.0 \text{ mg}=0.125×16=2.0 mg.
Concentration 1 mg/0.5 mL=2 mg/1.0 mL1 \text{ mg}/0.5 \text{ mL} = 2 \text{ mg}/1.0
\text{ mL}1 mg/0.5 mL=2 mg/1.0 mL. Volume = 1.0 mL.
Difficulty: Moderate
NCLEX Client Needs Category: Physiological Integrity – Pharmacological and
Parenteral Therapies
Keywords: weight-based, proportional reasoning, decimals
7. The provider orders 1.5 mg of a drug; the only tablets available are 2-mg scored
tablets. How should the nurse obtain the dose?
A. Give 1 tablet
B. Give ½ tablet
C. Give ¾ tablet
D. Give 1¼ tablets
, Henke's Med-Math Dosage-Calculation, Preparation, and Administration, 9th Edition
(Buchholz,
✅ Correct Answer: C
Rationale: ¾×2 mg=1.5 mg¾ × 2 \text{ mg} = 1.5 \text{ mg}¾×2 mg=1.5 mg. Fraction
→ decimal equivalence supports safe tablet splitting on a scored tablet.
Difficulty: Easy
NCLEX Client Needs Category: Physiological Integrity – Pharmacological and
Parenteral Therapies
Keywords: fractions, tablet splitting
8. An IVPB antibiotic 150 mg in 50 mL must infuse over 20 minutes. What pump
rate is set in mL/hr?
A. 100 mL/hr
B. 120 mL/hr
C. 150 mL/hr
D. 200 mL/hr
✅ Correct Answer: D
Rationale: Convert 20 min → 0.333 hr. Rate =50÷0.333≈150= 50 ÷ 0.333 ≈
150=50÷0.333≈150 is tempting—but exact: 50÷13=15050 ÷ \frac{1}{3} = 15050÷31
=150. Wait—pump rates are typically set in whole numbers; however, most facilities use
the proportional setup: 50 mL20 min×60 min1 hr=150 mL/hr\frac{50\ \text{mL}}{20\
\text{min}} × \frac{60\ \text{min}}{1\ \text{hr}} = 150 \text{ mL/hr}20 min50 mL
×1 hr60 min=150 mL/hr.
Therefore correct setting: 150 mL/hr.
(If a device only allows preset steps, choose the closest per policy.)
Difficulty: Moderate
NCLEX Client Needs Category: Physiological Integrity – Pharmacological and
Parenteral Therapies
Keywords: IV rate, unit conversion, proportional reasoning
9. A clinician evaluates carbohydrate intake using D12.5W. How many grams of
dextrose are delivered in 250 mL of D12.5W?
A. 12.5 g
B. 25 g
C. 31.25 g
D. 62.5 g
✅ Correct Answer: C
Rationale: 12.5% = 12.5 g per 100 mL. 12.5/100×250=31.25 g12.5/100 × 250 = 31.25
, Henke's Med-Math Dosage-Calculation, Preparation, and Administration, 9th Edition
(Buchholz,
\text{ g}12.5/100×250=31.25 g.
Difficulty: Moderate
NCLEX Client Needs Category: Physiological Integrity – Pharmacological and
Parenteral Therapies
Keywords: percent solutions, decimals
10. The order is metronidazole 1.5 g PO now. Tablets available are 500 mg. How
many tablets?
A. 2
B. 3
C. 4
D. 5
✅ Correct Answer: B
Rationale: 1.5 g=1500 mg1.5 \text{ g} = 1500 \text{ mg}1.5 g=1500 mg.
1500÷500=31500 ÷ 500 = 31500÷500=3 tablets. (Arithmetic with decimals/metric
place values.)
Difficulty: Easy
NCLEX Client Needs Category: Physiological Integrity – Pharmacological and
Parenteral Therapies
Keywords: tablets, place value, simple division
11. The prescriber reduces a patient’s beta-blocker from 50 mg to 40 mg daily due to
bradycardia. What percentage reduction is this?
A. 10%
B. 15%
C. 20%
D. 25%
✅ Correct Answer: C
Rationale: Reduction =50−40=10 mg= 50 − 40 = 10 \text{ mg}=50−40=10 mg. Percent
=10/50=0.20=20%= 10/50 = 0.20 = 20\%=10/50=0.20=20%.
Difficulty: Easy
NCLEX Client Needs Category: Physiological Integrity – Pharmacological and
Parenteral Therapies
Keywords: percentages, dose adjustment
(Buchholz,
, Henke's Med-Math Dosage-Calculation, Preparation, and Administration, 9th Edition
(Buchholz,
CHAPTER 1: Arithmetic Needed for Dosage.
Each question has a clinical setup, 4 options, ✅ Correct Answer, and a clear rationale.
Methods highlighted including ratio–proportion, formula, and dimensional analysis,
with plenty of fractions/decimals/percentages.
1. A post-op adult is prescribed acetaminophen 650 mg PO q6h PRN. Tablets are
325 mg each. How many tablets should the nurse administer per dose?
A. 1
B. 1.5
C. 2
D. 3
✅ Correct Answer: C
Rationale: 650 mg÷325 mg/tab=2 tabs650 \text{ mg} ÷ 325 \text{ mg/tab} = 2 \text{
tabs}650 mg÷325 mg/tab=2 tabs. Using the formula method: D/H×V=650/325×1=2D/H
× V = 650/325 × 1 = 2D/H×V=650/325×1=2.
Difficulty: Easy
NCLEX Client Needs Category: Physiological Integrity – Pharmacological and
Parenteral Therapies
Keywords: tablets, formula method, decimals
2. A child is prescribed amoxicillin 250 mg PO. The suspension is 400 mg per 5
mL. How many milliliters should be given? (Use an oral syringe; round to the
nearest 0.1 mL.)
A. 2.5 mL
B. 3.1 mL
C. 3.5 mL
D. 4.0 mL
✅ Correct Answer: B
Rationale: Ratio–proportion 400:5=250:x⇒x=(250×5)/400=3.125 mL400:5 = 250:x
\Rightarrow x = (250×5)/400 = 3.125 \text{
mL}400:5=250:x⇒x=(250×5)/400=3.125 mL. Round to 3.1 mL for oral syringe
accuracy.
, Henke's Med-Math Dosage-Calculation, Preparation, and Administration, 9th Edition
(Buchholz,
Difficulty: Moderate
NCLEX Client Needs Category: Physiological Integrity – Pharmacological and
Parenteral Therapies
Keywords: suspension, ratio–proportion, rounding
3. A provider orders a 1% hydrocortisone cream to apply as a 30-g thin layer to a
rash. How many milligrams of drug are in that 30-g dose?
A. 30 mg
B. 300 mg
C. 3,000 mg
D. 0.3 mg
✅ Correct Answer: B
Rationale: 1% w/w = 1 g per 100 g. 0.01×30 g=0.3 g=300 mg0.01 × 30 \text{ g} = 0.3
\text{ g} = 300 \text{ mg}0.01×30 g=0.3 g=300 mg.
Difficulty: Moderate
NCLEX Client Needs Category: Physiological Integrity – Pharmacological and
Parenteral Therapies
Keywords: percent strength, conversions, decimals
4. The order is heparin 7,500 units SQ. The vial reads 5,000 units/mL. What
volume will the nurse draw up?
A. 0.5 mL
B. 1.0 mL
C. 1.5 mL
D. 2.0 mL
✅ Correct Answer: C
Rationale: Dimensional analysis: 7,500 units×1 mL5,000 units=1.5 mL7{,}500\
\text{units} × \frac{1\ \text{mL}}{5{,}000\ \text{units}} = 1.5\
\text{mL}7,500 units×5,000 units1 mL=1.5 mL.
Difficulty: Easy
NCLEX Client Needs Category: Physiological Integrity – Pharmacological and
Parenteral Therapies
Keywords: units/mL, dimensional analysis
, Henke's Med-Math Dosage-Calculation, Preparation, and Administration, 9th Edition
(Buchholz,
5. The patient needs morphine 2 mg IV push. The vial is 10 mg/mL. What volume
should be administered?
A. 0.1 mL
B. 0.2 mL
C. 0.5 mL
D. 1.0 mL
✅ Correct Answer: B
Rationale: Formula: D/H×V=2/10×1=0.2 mLD/H × V = 2/10 × 1 = 0.2 \text{
mL}D/H×V=2/10×1=0.2 mL.
Difficulty: Easy
NCLEX Client Needs Category: Physiological Integrity – Pharmacological and
Parenteral Therapies
Keywords: IV push, formula method
6. A pediatric order is albuterol 0.125 mg/kg nebulized for a 16-kg child. The
solution is 1 mg/0.5 mL. What volume is prepared?
A. 0.5 mL
B. 0.8 mL
C. 1.0 mL
D. 1.5 mL
✅ Correct Answer: C
Rationale: Dose =0.125×16=2.0 mg= 0.125×16 = 2.0 \text{ mg}=0.125×16=2.0 mg.
Concentration 1 mg/0.5 mL=2 mg/1.0 mL1 \text{ mg}/0.5 \text{ mL} = 2 \text{ mg}/1.0
\text{ mL}1 mg/0.5 mL=2 mg/1.0 mL. Volume = 1.0 mL.
Difficulty: Moderate
NCLEX Client Needs Category: Physiological Integrity – Pharmacological and
Parenteral Therapies
Keywords: weight-based, proportional reasoning, decimals
7. The provider orders 1.5 mg of a drug; the only tablets available are 2-mg scored
tablets. How should the nurse obtain the dose?
A. Give 1 tablet
B. Give ½ tablet
C. Give ¾ tablet
D. Give 1¼ tablets
, Henke's Med-Math Dosage-Calculation, Preparation, and Administration, 9th Edition
(Buchholz,
✅ Correct Answer: C
Rationale: ¾×2 mg=1.5 mg¾ × 2 \text{ mg} = 1.5 \text{ mg}¾×2 mg=1.5 mg. Fraction
→ decimal equivalence supports safe tablet splitting on a scored tablet.
Difficulty: Easy
NCLEX Client Needs Category: Physiological Integrity – Pharmacological and
Parenteral Therapies
Keywords: fractions, tablet splitting
8. An IVPB antibiotic 150 mg in 50 mL must infuse over 20 minutes. What pump
rate is set in mL/hr?
A. 100 mL/hr
B. 120 mL/hr
C. 150 mL/hr
D. 200 mL/hr
✅ Correct Answer: D
Rationale: Convert 20 min → 0.333 hr. Rate =50÷0.333≈150= 50 ÷ 0.333 ≈
150=50÷0.333≈150 is tempting—but exact: 50÷13=15050 ÷ \frac{1}{3} = 15050÷31
=150. Wait—pump rates are typically set in whole numbers; however, most facilities use
the proportional setup: 50 mL20 min×60 min1 hr=150 mL/hr\frac{50\ \text{mL}}{20\
\text{min}} × \frac{60\ \text{min}}{1\ \text{hr}} = 150 \text{ mL/hr}20 min50 mL
×1 hr60 min=150 mL/hr.
Therefore correct setting: 150 mL/hr.
(If a device only allows preset steps, choose the closest per policy.)
Difficulty: Moderate
NCLEX Client Needs Category: Physiological Integrity – Pharmacological and
Parenteral Therapies
Keywords: IV rate, unit conversion, proportional reasoning
9. A clinician evaluates carbohydrate intake using D12.5W. How many grams of
dextrose are delivered in 250 mL of D12.5W?
A. 12.5 g
B. 25 g
C. 31.25 g
D. 62.5 g
✅ Correct Answer: C
Rationale: 12.5% = 12.5 g per 100 mL. 12.5/100×250=31.25 g12.5/100 × 250 = 31.25
, Henke's Med-Math Dosage-Calculation, Preparation, and Administration, 9th Edition
(Buchholz,
\text{ g}12.5/100×250=31.25 g.
Difficulty: Moderate
NCLEX Client Needs Category: Physiological Integrity – Pharmacological and
Parenteral Therapies
Keywords: percent solutions, decimals
10. The order is metronidazole 1.5 g PO now. Tablets available are 500 mg. How
many tablets?
A. 2
B. 3
C. 4
D. 5
✅ Correct Answer: B
Rationale: 1.5 g=1500 mg1.5 \text{ g} = 1500 \text{ mg}1.5 g=1500 mg.
1500÷500=31500 ÷ 500 = 31500÷500=3 tablets. (Arithmetic with decimals/metric
place values.)
Difficulty: Easy
NCLEX Client Needs Category: Physiological Integrity – Pharmacological and
Parenteral Therapies
Keywords: tablets, place value, simple division
11. The prescriber reduces a patient’s beta-blocker from 50 mg to 40 mg daily due to
bradycardia. What percentage reduction is this?
A. 10%
B. 15%
C. 20%
D. 25%
✅ Correct Answer: C
Rationale: Reduction =50−40=10 mg= 50 − 40 = 10 \text{ mg}=50−40=10 mg. Percent
=10/50=0.20=20%= 10/50 = 0.20 = 20\%=10/50=0.20=20%.
Difficulty: Easy
NCLEX Client Needs Category: Physiological Integrity – Pharmacological and
Parenteral Therapies
Keywords: percentages, dose adjustment
