Significant Digits

Significant digits (sometimes called significant figures) help us convey the uncertainty in our data. It is important to reflect the appropriate precision of the result by rounding the final answer to the correct number of significant digits.

1.493287432 cm vs 1.5cm plays a huge difference.

Normally we keep additional precision in the intermediate steps and only round when the final answer is stated.

Addition and subtraction: Keep the same number of significant digits after (or in front of) the decimal point as in the least precise of the quantities used in the calculation.

Multiplication and division: The number of significant digits in the final answer should be the same as the least precise quantity used in the calculation