Which of the following have same number of significant figures?
A. 0.00253
B. 1.0003
C. 15.0
D. 163
Choose the correct answer from the options given below

Solution

Chemistry ma’am · 3 steps

Leading zeros are only placeholders, so 0.00253 has just 3 significant figures, the same as 15.0 and 163.

1. The counting rules. All non-zero digits count. Zeros between non-zero digits count. Zeros before the first non-zero digit never count, and trailing zeros after a decimal point do count.

   Number	Which digits count	Significant figures
   A. 0.00253	2, 5, 3 (the leading zeros only fix the decimal place)	3
   B. 1.0003	1, 0, 0, 0, 3 (zeros trapped between non-zero digits)	5
   C. 15.0	1, 5, 0 (trailing zero after the decimal point)	3
   D. 163	1, 6, 3	3

2. Compare. A, C and D each have 3 significant figures. B is the odd one out with 5.
3. So. The numbers with the same count are A, C and D, which is option (a).

The idea to keep. Start counting at the first non-zero digit. Zeros in between count, and zeros at the end count only when there is a decimal point.

Answer from the NTA final answer key. Solution by PrepWiser.