Addition and Subtraction with Significant figures #8211; When we add or subtract, the final result should retain as many decimal places as are there in the number with the least decimal places. i.e. if we add 48.41, 253.1 and 2.189, then we will get 303.699 but in case of significant figures, final result will be 303.7 (taking the least decimal place and rounding it).