Chapter 1 —Medication Orders & Tablet
Calculations
Stem: Which written drug order is unsafe because of a
formatting error that increases risk of tenfold dosing?
A. 0.5 mg
B. 5.0 mg
C. 5 mg
D. 05 mg
Correct Answer: B
Rationales:
, • Correct (B): 5.0 mg — Unsafe because the trailing zero
after a decimal may be misread (e.g., as 50 mg) if the
decimal point is missed. Best practice: omit trailing zeros.
• A (0.5 mg): This is correct formatting for a fraction of a
milligram (leading zero present), so it's safe.
• C (5 mg): Correctly written without trailing zero; safe.
• D (05 mg): Leading zero before a whole number is
nonstandard and could be misinterpreted, but it is less
commonly flagged than a trailing zero; still poor format
but not the classic trailing-zero error.
Teaching Point: Never use trailing zeros (e.g., write 5 mg, not
5.0 mg).
2.
Chapter Reference: Chapter 1 — Section: Metric Conversions —
Title: Gram to Milligram Conversion
Stem: Convert 0.25 g to milligrams (mg).
A. 25 mg
B. 250 mg
C. 2,500 mg
D. 0.25 mg
Correct Answer: B
Rationales:
, • Correct (B): 0.25 g × 1000 mg/g = 250 mg. Step: 0.25 ×
1000 = 250.
• A (25 mg): Reflects moving the decimal one place instead
of three (wrong conversion factor).
• C (2,500 mg): Reflects moving the decimal one place too
far (×10 error).
• D (0.25 mg): Fails to convert grams to milligrams (no
multiplication by 1000).
Teaching Point: Multiply grams by 1,000 to get milligrams.
3.
Chapter Reference: Chapter 1 — Section: Metric Conversions —
Title: Micrograms to Milligrams
Stem: How many milligrams (mg) are in 500 micrograms (mcg)?
A. 0.05 mg
B. 0.5 mg
C. 5 mg
D. 50 mg
Correct Answer: B
Rationales:
• Correct (B): 500 mcg ÷ 1000 mcg/mg = 0.5 mg. Step:
500/1000 = 0.5.
, • A (0.05 mg): Result of dividing by 10,000 (decimal moved
one extra place).
• C (5 mg): Decimal shifted wrong direction (×10 error).
• D (50 mg): Off by factor of 100 (incorrect conversion).
Teaching Point: 1,000 micrograms = 1 milligram.
4.
Chapter Reference: Chapter 1 — Section: Dose Calculations —
Title: Concentration & Volume Calculation (Oral Suspension)
Stem: Order: 125 mg of medication PO. Supply: 250 mg per 5
mL suspension. How many mL should you give?
A. 1.25 mL
B. 2.0 mL
C. 2.5 mL
D. 3.0 mL
Correct Answer: C
Rationales:
• Correct (C): Use ratio (Desired ÷ Have) × Volume = (125 mg
÷ 250 mg) × 5 mL = 0.5 × 5 = 2.5 mL.
• A (1.25 mL): Incorrectly halved again (likely used 125/500
or decimal placement error).
• B (2.0 mL): Incorrect rounding or wrong
numerator/denominator.
Calculations
Stem: Which written drug order is unsafe because of a
formatting error that increases risk of tenfold dosing?
A. 0.5 mg
B. 5.0 mg
C. 5 mg
D. 05 mg
Correct Answer: B
Rationales:
, • Correct (B): 5.0 mg — Unsafe because the trailing zero
after a decimal may be misread (e.g., as 50 mg) if the
decimal point is missed. Best practice: omit trailing zeros.
• A (0.5 mg): This is correct formatting for a fraction of a
milligram (leading zero present), so it's safe.
• C (5 mg): Correctly written without trailing zero; safe.
• D (05 mg): Leading zero before a whole number is
nonstandard and could be misinterpreted, but it is less
commonly flagged than a trailing zero; still poor format
but not the classic trailing-zero error.
Teaching Point: Never use trailing zeros (e.g., write 5 mg, not
5.0 mg).
2.
Chapter Reference: Chapter 1 — Section: Metric Conversions —
Title: Gram to Milligram Conversion
Stem: Convert 0.25 g to milligrams (mg).
A. 25 mg
B. 250 mg
C. 2,500 mg
D. 0.25 mg
Correct Answer: B
Rationales:
, • Correct (B): 0.25 g × 1000 mg/g = 250 mg. Step: 0.25 ×
1000 = 250.
• A (25 mg): Reflects moving the decimal one place instead
of three (wrong conversion factor).
• C (2,500 mg): Reflects moving the decimal one place too
far (×10 error).
• D (0.25 mg): Fails to convert grams to milligrams (no
multiplication by 1000).
Teaching Point: Multiply grams by 1,000 to get milligrams.
3.
Chapter Reference: Chapter 1 — Section: Metric Conversions —
Title: Micrograms to Milligrams
Stem: How many milligrams (mg) are in 500 micrograms (mcg)?
A. 0.05 mg
B. 0.5 mg
C. 5 mg
D. 50 mg
Correct Answer: B
Rationales:
• Correct (B): 500 mcg ÷ 1000 mcg/mg = 0.5 mg. Step:
500/1000 = 0.5.
, • A (0.05 mg): Result of dividing by 10,000 (decimal moved
one extra place).
• C (5 mg): Decimal shifted wrong direction (×10 error).
• D (50 mg): Off by factor of 100 (incorrect conversion).
Teaching Point: 1,000 micrograms = 1 milligram.
4.
Chapter Reference: Chapter 1 — Section: Dose Calculations —
Title: Concentration & Volume Calculation (Oral Suspension)
Stem: Order: 125 mg of medication PO. Supply: 250 mg per 5
mL suspension. How many mL should you give?
A. 1.25 mL
B. 2.0 mL
C. 2.5 mL
D. 3.0 mL
Correct Answer: C
Rationales:
• Correct (C): Use ratio (Desired ÷ Have) × Volume = (125 mg
÷ 250 mg) × 5 mL = 0.5 × 5 = 2.5 mL.
• A (1.25 mL): Incorrectly halved again (likely used 125/500
or decimal placement error).
• B (2.0 mL): Incorrect rounding or wrong
numerator/denominator.
