What Are the Common Rules When Adding Significant Figures?

When adding numbers, the rules of significant figures dictate that the sum should be rounded to the same place as the least significant place of the number, with the least number of places after the decimal point. Significant figures are important when recording and relaying scientific data because they provide the reader with an idea of how best one can report/measure data.

For example, if 12.2, 3.66, 214.39 and 2.472 are to be added, the answer would be 232.7 because the number with least decimal places is 12.2 meaning the answer should be rounded to 0.1 decimal place. Other rules include: