To answer to the question above, when adding or subtracting measurements (numbers), the result must have the same number of decimal places as the number in the problem with the fewest decimal places.
24.545 + 307.3 = 331.845
However, the answer must be given to the correct number of decimal places, in this case, 1 in 307.3.
So the result of the addition of 24.545 and 307.3 should be 331.8.
