To account for the uncertainty inherent in any measured quantity, we report measured quantities using significant figures or sig figs, which are the number of digits in a measurement you report based on how certain you are of your measurement. Reporting sig figs properly is important, and we need to account for sig figs when performing mathematical calculations using measured quantities. There are rules for determining the number of sig figs in a given measured quantity. There are also rules for carrying sig figs through mathematical calculations.
Watch these two videos to learn how to count sig figs for a given quantity.
Source: Khan Academy, https://youtu.be/eCJ76hz7jPM, https://youtu.be/eMl2z3ezlrQ
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