What is the decimal of 9% ?

Appeared in: OSSSC Nursing Officer-2021

Explanation

The term 'percent' (%) means 'per hundred', so 9% is equivalent to 9 out of 100.
To convert a percentage to a decimal, you divide the number by 100.
Calculation: 9 ÷ 100 = 0.09.
A common shortcut is to move the decimal point two places to the left and remove the '%' sign. For the number 9, the decimal is at the end (9.), so moving it two places left results in 0.09.

Option A: This value represents 90%. The decimal point was incorrectly moved only one place to the left instead of two.
Option B: This value represents 0.9%. The decimal point was incorrectly moved three places to the left.
Option D: This value represents 0.09%. The decimal point was incorrectly moved four places to the left.

Clinical Relevance

Nursing practice connection: This is primarily an exam-oriented knowledge point with limited direct bedside application, so retain Percentage to Decimal Conversion as background academic context rather than a clinical decision trigger.
Accurate conversion between percentages and decimals is a fundamental math skill required for safe nursing practice, especially in medication dosage calculations.
Errors in decimal placement can lead to significant medication errors (e.g., a tenfold overdose or underdose), which can have severe consequences for patient safety.
Nurses frequently work with percentage-based solutions (e.g., 0.9% Normal Saline, 5% Dextrose) and must be able to use these values correctly in calculations.

How to Approach the Question

Identify the core task: The question asks to convert a percentage (9%) into its decimal form.
Recall the definition of 'percent': It means 'out of one hundred'.
Apply the conversion rule: To change a percent to a decimal, divide the number by 100.
Alternatively, use the shortcut: Move the decimal point two places to the left. For a whole number like 9, the decimal is assumed to be at the end (9.).
Perform the move: Moving the decimal two places left from 9. gives .09, which is written as 0.09.
Compare the result with the given options to find the correct match.

Concept Tested & Keywords

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