In which of the following pairs do both numbers contain the same number of significant figures?

• A. 0.00450 and 2.30
• B. 100.0 and 10.0
• C. 1.200 and 12.0
• D. 0.040 and 0.004

Answer: (A)

Verified step by step guidance

1. Recall the rules for counting significant figures: all nonzero digits are significant; zeros between nonzero digits are significant; leading zeros are not significant; trailing zeros in a decimal number are significant.
2. Count the significant figures in each number of the first pair: 0.00450 has 3 significant figures (the '4', '5', and the trailing zero), and 2.30 has 3 significant figures (the '2', '3', and the trailing zero).
3. Count the significant figures in each number of the second pair: 100.0 has 4 significant figures (the '1', two zeros, and the decimal zero), and 10.0 has 3 significant figures (the '1', zero, and the decimal zero).
4. Count the significant figures in each number of the third pair: 1.200 has 4 significant figures (the '1', '2', and two trailing zeros), and 12.0 has 3 significant figures (the '1', '2', and the trailing zero).
5. Count the significant figures in each number of the fourth pair: 0.040 has 2 significant figures (the '4' and the trailing zero), and 0.004 has 1 significant figure (the '4' only). Compare the counts to identify which pair has matching significant figures.