This requires you to round-off the value, 30.239 m, to 30.24 m. You will report the correct calculated answer as 30.24 m . A different method is used to find the correct number of significant digits when multiplying or dividing measurements. After performing the calculation, note the factor that has the least number of significant digits. Round the product or quotient to this number of digits. Solve the following problems and report answers with appropriate number of significant digits.
Many calculators display several additional, meaningless digits, some always display only two.
Be sure to record your answer with the correct number of significant digits. If you counted four laps for a runner and measured the time to be 2.34 minutes. The number of labs does not have an uncertainty, but the measured time does. Visit this site and take the quiz.