The following rules for Arithmetical operations with significant figures that make final result more consistent with the Precision of the measured value.
For Addition and Subtraction
In both addition and subtraction, the final result should retain as many decimal places as are there in the number with the least decimal places.
Example:- We have three length measured value 2.1 m, 1.78 m, 2.046 m and the Sum of all these values are 5.926 m which is rounded off to 5.9 m.
For Multiplication and Division
In multiplication or division, the final result should retain as many significant figures, as they are in the original number with the least significant figures.