Any properly recorded measurement can be said to have a maximum uncertainty or error of plus or minus one-half its last digit.
Significant figures give an indication of the precision attained when taking measurements.
Move to the right until you reach the first non-zero digit. Count that digit and all others to the right. The value with the least significant digits sets the standard for the degree of precision for your measurements. At times, measurements are taken that do not require high accuracy. In cases like this, the reading should be rounded and recorded at a lower level of accuracy.