# Question #94c0e

Terminal zeroes before a decimal point are generally not sugnificant. They just serve as placeholders to give the actual significant digits their proper place values. Thus $530 , 405 , 000$ is likely to be accurate only to the nearest thousand, but we need the last three zeroes to distinguish the number from $530 , 405$.
Terminal zeroes after a decimal point are significant because they are not mere placeholders. Thus $5.0$ must have two significant digits instead of one. If $530 , 405 , 000$ is accurate to the nearest multiple of $100$ (i.e. the number is accurate enough for the first terminal zero to be a seventh significant digit), we can indicate that by including an extra zero in scientific notation where all digits but one are after the decimal point. Thus, $5.30405 \textcolor{b l u e}{0} \times {10}^{8}$ has the last zero after the decimal point, so it is indicated as an extra significant digit.