Does a negative sign (−) count as a significant digit in measurements?

A negative sign does not count as a significant digit in measurements. Instead, the sign indicates the direction or nature of the value (whether it is below zero) rather than contributing to the precision or accuracy of the digits representing the magnitude of the measurement.

Significant digits are the numbers in a measurement that carry meaning about its precision, which includes all non-zero digits and any zeros that are sandwiched between significant digits or are trailing zeros in a decimal. The presence of the negative sign does not change the rules governing which digits are considered significant and instead serves just to communicate that the quantity is a negative value. Thus, the understanding of significant digits is solely concerned with the numerical portion of the measurement itself, highlighting that the correct answer is contrary to what was suggested.