Well even this source then agrees that it's at the very least ambiguous. Someone looking at the number will not be able to tell if the 3 is rounded or if you measured it exactly to 530,000. IMO you should never leave it as such, because some people may assume one and some may assume the other. You should ideally always use scientific notation because it avoids such confusion and can only be interpreted one way. Personally, if I was marking homework and got an answer like 4970 I would take it as 4 sig figs because there is nothing to indicate otherwise.

Yes, it does leave it to be ambiguous. scientific notation would help, but on some of these homework problems (im assuming online) they dont necessarily ask for scientific notation or allow for it to be entered.

This post was edited by cialda on May 24 2013 07:02am

Well, his homework said "scientific notation is optional", so it probably accepts it.
Also, consider this. If I have 530,000 how do I know if that's 2 sig figs (let's say it was 529,231) or 3 sig figs (let's say it was 529,789) or 4 sig figs (let's say it was 530,021), etc. Just because the 3 is the last non-zero number doesn't mean that it's the one that got rounded. I could just happen to round up or down to a zero.

Yes and I realize that. Was agreeing it was ambiguous and that could be a problem. I didn't read entire thread as to if his hw accepted sci notation