https://www.khanacademy.org/math/arithmetic-home/arith-review-decimals/arithmetic-significant-figures-tutorial/v/significant-figures

Significant figures are the number of digits in a value, often a measurement, that contribute to the degree of accuracy of the value. We start counting significant ...

https://en.wikipedia.org/wiki/Significant_figures

The significant figures of a number are digits that carry meaning contributing to its measurement resolution. This includes all digits ...

http://chemistry.bd.psu.edu/jircitano/sigfigs.html

There are three rules on determining how many significant figures are in a number: .... In mathematical operations involving significant figures, the answer is  ...

https://www.ducksters.com/kidsmath/significant_digits_or_figures.php

Kids learn about significant digits and figures. How to determine how many digits are significant in a number. Example math problems.

https://www-users.york.ac.uk/~mb55/msc/maths/sigfig.htm

Oct 1, 2007 ... Brush up your maths: Significant figures. Rounding. When we carry out calculations, we often get the result as a number with many digits.

https://www.purplemath.com/modules/rounding2.htm

Another consideration in rounding is when you are required to round to "an appropriate number of significant digits". What are significant digits? Well, they're sort ...

https://www.omnicalculator.com/math/sig-fig

Our significant figures calculator works in two modes - it performs arithmetic operations on multiple numbers (for example 4.18 / 2.33 ) or simply rounds a number ...

http://mathsfirst.massey.ac.nz/Algebra/Decimals/SigFig.htm

Rules for significant figures: If the number has a decimal point, the leading "0"s are not significant. All other digits (including trailing "0"s) are significant.

https://www.chem.tamu.edu/class/fyp/mathrev/mr-sigfg.html

Math Skills Review ... If I am more precise, I might get 216 mm (3 significant figures). An even ... In any measurement, the number of significant figures is critical.

https://www.physics.uoguelph.ca/tutorials/sig_fig/SIG_dig.htm

The number of significant digits in an answer to a calculation will depend on the number of significant digits in the given data, as discussed in the rules below.