CALCULATION OF DRUG DOSAGES: A WORK TEXT
12TH EDITION
AUTHOR(S)SHEILA J. OGDEN; LINDA FLUHARTY
CHAPTER 1: FRACTIONS PRETEST
CALCULATION OF DRUG DOSAGES — 12TH EDITION
20 ORIGINAL DOSAGE-CALCULATION PRACTICE QUESTIONS
QUESTION 1
Category: [Basic Mathematics]
Difficulty: Foundational
Question:
A nursing student is reviewing fractions before beginning medication-dosage
calculations. Which fraction is equivalent to 3/4?
A. 6/10
B. 9/12
C. 12/20
D. 15/24
Correct Answer: B. 9/12
Calculation / Reasoning:
Multiply both the numerator and denominator of 3/4 by 3:
3×3=9
4 × 3 = 12
Therefore:
3/4 = 9/12
Rationale:
1
,Equivalent fractions have the same value even though their numerators and
denominators differ. Multiplying both parts of a fraction by the same nonzero number
preserves its value. This skill is important when manipulating fractions during dosage
calculations.
Why the other options are incorrect:
A. 6/10 = 3/5, not 3/4.
B. 9/12 = 3/4 and is correct.
C. 12/20 = 3/5, not 3/4.
D. 15/24 = 5/8, not 3/4.
Clinical Focus: Recognizing equivalent fractions supports accurate medication-
mathematics calculations.
QUESTION 2
Category: [Fractions]
Difficulty: Foundational
Question:
A medication calculation requires the nurse to add 1/3 + 1/6. What is the correct result?
A. 1/9
B. 1/2
C. 2/9
D. 2/3
Correct Answer: B. 1/2
Calculation / Reasoning:
The least common denominator of 3 and 6 is 6.
1/3 = 2/6
Therefore:
2/6 + 1/6 = 3/6 = 1/2
Rationale:
Fractions must have a common denominator before their numerators can be added.
After converting 1/3 to 2/6, the fractions can be added directly. Reducing 3/6 produces
1/2.
2
,Why the other options are incorrect:
A. 1/9 results from incorrectly adding denominators.
B. 1/2 is correct.
C. 2/9 reflects an incorrect denominator calculation.
D. 2/3 does not equal the sum.
Clinical Focus: Always establish a common denominator before adding or subtracting
fractions.
QUESTION 3
Category: [Fractions]
Difficulty: Foundational
Question:
A medication cup contains a measured amount represented as 5/6 cup. A portion
equal to 1/3 cup is removed. How much remains?
A. 1/2 cup
B. 2/3 cup
C. 1/3 cup
D. 3/4 cup
Correct Answer: A. 1/2 cup
Calculation / Reasoning:
Convert 1/3 to sixths:
1/3 = 2/6
Then:
5/6 − 2/6 = 3/6
Reduce:
3/6 = 1/2
Rationale:
The fractions must have a common denominator before subtraction. Expressing both
quantities in sixths allows the subtraction to be performed correctly.
Why the other options are incorrect:
3
, A. 1/2 cup is correct.
B. 2/3 cup results from an incorrect subtraction.
C. 1/3 cup does not represent the remaining amount.
D. 3/4 cup cannot be obtained from the stated subtraction.
Clinical Focus: Fraction subtraction should be completed only after establishing
compatible denominators.
QUESTION 4
Category: [Fractions]
Difficulty: Moderate
Question:
A nurse needs to calculate:
2/3 × 3/4
What is the correct answer?
A. 1/4
B. 1/2
C. 5/7
D. 6/7
Correct Answer: B. 1/2
Calculation / Reasoning:
Multiply numerators:
2×3=6
Multiply denominators:
3 × 4 = 12
Therefore:
6/12 = 1/2
Rationale:
When multiplying fractions, multiply the numerators together and the denominators
together. The resulting fraction should then be reduced to its simplest form.
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12TH EDITION
AUTHOR(S)SHEILA J. OGDEN; LINDA FLUHARTY
CHAPTER 1: FRACTIONS PRETEST
CALCULATION OF DRUG DOSAGES — 12TH EDITION
20 ORIGINAL DOSAGE-CALCULATION PRACTICE QUESTIONS
QUESTION 1
Category: [Basic Mathematics]
Difficulty: Foundational
Question:
A nursing student is reviewing fractions before beginning medication-dosage
calculations. Which fraction is equivalent to 3/4?
A. 6/10
B. 9/12
C. 12/20
D. 15/24
Correct Answer: B. 9/12
Calculation / Reasoning:
Multiply both the numerator and denominator of 3/4 by 3:
3×3=9
4 × 3 = 12
Therefore:
3/4 = 9/12
Rationale:
1
,Equivalent fractions have the same value even though their numerators and
denominators differ. Multiplying both parts of a fraction by the same nonzero number
preserves its value. This skill is important when manipulating fractions during dosage
calculations.
Why the other options are incorrect:
A. 6/10 = 3/5, not 3/4.
B. 9/12 = 3/4 and is correct.
C. 12/20 = 3/5, not 3/4.
D. 15/24 = 5/8, not 3/4.
Clinical Focus: Recognizing equivalent fractions supports accurate medication-
mathematics calculations.
QUESTION 2
Category: [Fractions]
Difficulty: Foundational
Question:
A medication calculation requires the nurse to add 1/3 + 1/6. What is the correct result?
A. 1/9
B. 1/2
C. 2/9
D. 2/3
Correct Answer: B. 1/2
Calculation / Reasoning:
The least common denominator of 3 and 6 is 6.
1/3 = 2/6
Therefore:
2/6 + 1/6 = 3/6 = 1/2
Rationale:
Fractions must have a common denominator before their numerators can be added.
After converting 1/3 to 2/6, the fractions can be added directly. Reducing 3/6 produces
1/2.
2
,Why the other options are incorrect:
A. 1/9 results from incorrectly adding denominators.
B. 1/2 is correct.
C. 2/9 reflects an incorrect denominator calculation.
D. 2/3 does not equal the sum.
Clinical Focus: Always establish a common denominator before adding or subtracting
fractions.
QUESTION 3
Category: [Fractions]
Difficulty: Foundational
Question:
A medication cup contains a measured amount represented as 5/6 cup. A portion
equal to 1/3 cup is removed. How much remains?
A. 1/2 cup
B. 2/3 cup
C. 1/3 cup
D. 3/4 cup
Correct Answer: A. 1/2 cup
Calculation / Reasoning:
Convert 1/3 to sixths:
1/3 = 2/6
Then:
5/6 − 2/6 = 3/6
Reduce:
3/6 = 1/2
Rationale:
The fractions must have a common denominator before subtraction. Expressing both
quantities in sixths allows the subtraction to be performed correctly.
Why the other options are incorrect:
3
, A. 1/2 cup is correct.
B. 2/3 cup results from an incorrect subtraction.
C. 1/3 cup does not represent the remaining amount.
D. 3/4 cup cannot be obtained from the stated subtraction.
Clinical Focus: Fraction subtraction should be completed only after establishing
compatible denominators.
QUESTION 4
Category: [Fractions]
Difficulty: Moderate
Question:
A nurse needs to calculate:
2/3 × 3/4
What is the correct answer?
A. 1/4
B. 1/2
C. 5/7
D. 6/7
Correct Answer: B. 1/2
Calculation / Reasoning:
Multiply numerators:
2×3=6
Multiply denominators:
3 × 4 = 12
Therefore:
6/12 = 1/2
Rationale:
When multiplying fractions, multiply the numerators together and the denominators
together. The resulting fraction should then be reduced to its simplest form.
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