Question

What is the value of the sum of 12.1100 + 18.0 + 1.012 as per the rule of significant figures

• A. 31.1220
• B. 31.122
• C. 31.12
• D. 31.1
• E. 31

Hint:

When adding or subtracting, always look for the number with the least number of digits after the decimal point. Your answer cannot be more precise than that.

Answer 1

The Correct Option is D

Step 1: Understanding the Concept:
The rule for addition and subtraction with significant figures states that the final answer should have the same number of decimal places as the term with the fewest decimal places.

Step 2: Detailed Explanation:
Identify the decimal places in each number:
• 12.1100 has 4 decimal places.
• 18.0 has 1 decimal place.
• 1.012 has 3 decimal places. The term with the fewest decimal places is 18.0 (1 decimal place). Therefore, the final answer must be rounded to 1 decimal place. First, perform the addition: \(12.1100 + 18.0 + 1.012 = 31.1220\). Now, round 31.1220 to 1 decimal place. The digit in the hundredths place is 2, which is less than 5, so we round down.

Step 3: Final Answer:
The sum is 31.1.