Significant figures

• The number of significant figures is the same as the number of digits that are known with certainty.
• Significant figures include all non-zero digits, but may also include zeroes between non-zero digits or at the end of a measurement if they indicate precision beyond the last non-zero digit.
• Zeroes placed to the left of a non-zero digit do not count towards the total number of significant figures unless they indicate a value less than one (e.g., 0.02).
• In calculations involving addition/subtraction, use the least precise number to determine how many decimal places to carry over.