I need help understanding the rule for adding or subtracting numbers that have uncertainty?

**the rule says: when you add or subtract numbers that have uncertainty, your answer can be no more certain than the least certain number.





What exactly does this mean? i dont understand.





suppose the question to be:





add the sum of 10.3 and 0.0201 with the correct number of sig figs. Report your answer in normal notation.





how does the rule apply?I need help understanding the rule for adding or subtracting numbers that have uncertainty?
you can only add or subtract on the same number of digits. Therefore, in your example you would add 10.3 + .0 = 10.3





Look at another example:





10.3 + 0.4592 =


10.3 + 0.5 = 10.8








10.30 + 0.4592 =


10.30 + 0.46 = 10.76