Significant figures, also known as significant digits or sig figs, are specific digits within a number that carry both reliability and necessity in conveying a particular quantity. They are used to report a value, measured or calculated, to the correct number of decimal places or digits that will reflect the precision of the value. The number of significant figures in a measurement is equal to the number of digits that are known with some degree of confidence. Here are some rules to determine the number of significant figures:

• All nonzero digits are significant.
• All zeros between nonzero digits are significant.
• Zeros to the left of the first nonzero digit are not significant.
• Zeros to the right of the last nonzero digit are significant only if the number contains a decimal point.

For example, the number 114.8 mm has four significant figures, and the number 2.98 L has three significant figures. Significant figures are important in scientific or technical measurements because they indicate the actual value within an acceptable range of uncertainty. They also help us round off measurement values or the outcome of a calculation.