I understand significant figures all and well when there is just one calculation, but if there are multiple calculations…
(a * b) + (c * d)
I’m not sure quite how I’d solve such a problem with significant figures. On one hand, I could solve a * b, and c * d, recording the number of significant figures but not rounding the results, and then adding the two rounded numbers together but applying the sig fig rules for the rounded numbers. Is this right? Wrong?
But this is quite a bit of work, and seems rather superfluous.
On the other hand, could I just ignore significant figure rules until the last operation? That doesn’t seem right, since the figures used in that final calculation wouldn’t be properly based on significant figure rules.
