When Zachary adds 26.64 g to 12.557 g, how many significant figures should his final answer have?

• A. 3 significant figures
• B. 5 significant figures
• C. 4 significant figures
• D. 6 significant figures

Answer: (C)

Verified step by step guidance

1. Identify the number of significant figures in each given value. For 26.64 g, count the digits that are significant, and for 12.557 g, do the same.
2. Recall the rule for addition regarding significant figures: the result should be reported with the same number of decimal places as the number with the fewest decimal places in the values being added.
3. Determine the number of decimal places in each number. For example, 26.64 has two decimal places, and 12.557 has three decimal places.
4. Compare the decimal places and choose the smaller number of decimal places to decide how many decimal places the final answer should have.
5. Express the final answer with the correct number of decimal places, and then count the total significant figures in that rounded result to determine how many significant figures the final answer should have.