What is the rule with significant figures?

[soldier_on16]

Just need to clarify so I don't make any sto0pid mistakes

[Vincezor]

I think when multiplying/dividing, the final answer is the lowest number of sig figs.

For adding/subtracting, it is the lowest number of decimal places (though I never really fully understood this :S)

I'll have to confirm this with my teacher, but if I remember correctly from mid years it's like that...

[soldier_on16]

I'm referring to the FINAL answer after all the working out. Usually you use the WHOLE value on the calc when going through the calculations. I just need to know how many figs you go to when putting down the last answer

[HenryP]

Just follow the rules that Vincezor outlined. If the only calculations required include Multiplying/Dividing put your answer to the amount of significant figures that the least accurate data has.
The reason I think that its to the least decimal places when Adding/Subtracting is because the least accurate data is to data with the least amount of decimal places and not significant figures. If you think about it, it makes sense

[lillievee]

I've been hearing so many rules, I've always been taught to use the smallest number in the question within the numbers you used for working out, as a reference for sig figs.

Confused.

[luken93]

Think about it this way, if you weighed 12.345g on a 4 decimal scale, and then you took some of it, measured the amount you removed as being 2.34 on a 2 decimal scale, would you say you had 10.0g or 10.00g...