Question: how to find significant digits of log?
Answer: log(2.73×10–5) = log(2.73) + log(10–5) = 0.436 + (–5.00000000...) Here, the mantissa of the number to be logged is underlined, showing 3 significant figures. The same number of significant figures is underlined starting with the decimal point. After rounding, the correct answer is obtained.