Sig Fig Addition and Subtraction

[Reagan Smith 1H]

If there is a problem that includes addition/subtraction AND multiplication/division, which sig fig rule is supposed to be followed since there are different rules?

[nehashetty_2G]

I think it depends, but definitely follow rules both depending on the step you are on. Usually, you do sig figs at the end of a sequence (like in dimensional analysis); in that case you usually do the normal sig figs rules at the very end of the multiplication. But if you are adding and subtracting I would incorporate sig figs right then and there. Once again, it probably helps to do a few practice problems and figure out from there.

[AniP_2D]

Usually what I do when I'm adding/subtracting or multiplying/dividing, and the result is too long of a number to write down fully, is to just round the answer to 2 digits more than the amount of sig figs needed and then when I reach the final answer I will then round to the amount of sig figs needed.

[Rhea Shah 2F]

What I was taught was that for addition and subtraction, you keep the same amount of decimal points as the number with the lowest amount, even if this means the sum/difference doesn't have the same amount of sig figs as the one with the fewest. For multiplication and division, the product/quotient should have the same amount of sig figs as the number with the lowest amount of sig figs.

[Denise Montes 3B]

Rules for when you add/subtract sig figs is that you have to change your exponent to the smallest one and then when its time to divide/multiply (for the second half of the sig fig problem) instead of making the exponent the same, you can either subtract/add them depending on whether you're multiplying or dividing.

[Denise Montes 3B]

Additional note:
When dividing/multiplying with sig-figs you have to round your answer to the shortest number of the digits for the numbers that you're multiplying/dividing