I hate significant digits! Help me with this problem?

Question

(2.01 x 10^2) + (3.014 x 10^3) =

i dont understand. its mulitplying so i have to round to the number with least sig dig, but its also adding so i have to round to the number with least decimal places..... which is it?

Answer 1

The number with the least number of significent digits dictate the final answer, so the 2.01 has 3.

3.22 x 10^3

Answer 2

Only adding! 201 + 3014 = 3215; in this case all are significant.

Key: "ones" units are significant is both the addends ergo the answer is also significant in the "ones".

Previous answer is incorrect.

Answer 3

31.42