Which statement about leading zeros is true?

• A. Zeros to the left of the first nonzero digit are significant
• B. Zeros to the left of the first nonzero digit are not significant
• C. Trailing zeros with no decimal are always significant
• D. All zeros in a measured value are significant

Answer: (B)

Leading zeros act as placeholders that position the decimal point; they do not contribute to the precision of a measurement. For example, in 0.0123, the digits 1, 2, and 3 are the significant figures, while the zeros before the 1 are not. Significant figures reflect how precisely a value is known, not just the size of the number, so those leftmost zeros don’t add any precision. The other statements misstate how precision is conveyed: zeros to the left of the first nonzero digit are not significant; trailing zeros without a decimal point aren’t automatically significant; and not all zeros in a measured value are significant.