Significant figures

[athina.pap]

Hi! do you know to how many significant figures we should round up our results if the prompt of an exercise does not specify? also can you explain how do we calculate significant figures?

Thank you in advance.

[carpediem]

The standard is 3 significant figures.

However, if you do chemistry the significant figures varies from question to question - you have to look at the data given for that question, and answer with the lowest sig fig that the data has.

[Yahooo!]

3 significant figures

Okay soo... I tried typing it all out but was taking too long, so this website may help you: http://www.bbc.co.uk/schools/gcsebitesize/maths/number/roundestimaterev3.shtml

But there's a pre loaded APP on the Texas Calculator that converts your answer into significant figures. Scroll down to Sci Tools and its the first one: Sig-Fig Calculator.

Unless states otherwise it is always 3 sf

[onur basman]

3 significant figures

Okay soo... I tried typing it all out but was taking too long, so this website may help you: http://www.bbc.co.uk/schools/gcsebitesize/maths/number/roundestimaterev3.shtml

But there's a pre loaded APP on the Texas Calculator that converts your answer into significant figures. Scroll down to Sci Tools and its the first one: Sig-Fig Calculator.

Unless states otherwise it is always 3 sf

true , but you should be careful while changing your calculators settings

when you calculate big values it also rounds them to 3 significant figures for example 123 x 12 comes out 1.48E3 equaling 1480 instead of 1476

it took me a while to understand why I kept getting different answers than the answer key and lost a few points on the exam so be cautious before you change your settings.

[TykeDragon]

Or just do significant figures in your head? If it's a concept you've never encountered before, it may take a few minutes to get used to, but still

Remember only to round FINAL answers - preferably avoid rounding mid question, this may make the final answer inaccurate. Usually, markschemes seem to compensate it and allow both, but just to be certain..

To calculate significant figures, round the answers so that there are three integers. Any 0s after the last integer does not count as a significant figure, as these are unavoidable if writing a large number!

Eg, for 43896, look at the first three numbers - these will be your significant figures. however, looking after the 8, you can see it requires rounding up - so leave it at 43900. The 0s after do not count.

If putting a number like 10.01267 into 3 sf, leave it at 10.0 not just 10 - only write 10 if the answer is exact, so the 0 after the decimal place is significant here because although it doesn't round up to 10.1, there are still numbers after the 0.

For a very low decimal place number, such as 0.00048283, the 0s before the first integer do not count, as otherwise it would be 0.00 to 3 sf, and that's wrong! So, treat it like the large number above - 0.000483 (three significant integers, with the 2 rounded up to a 3, as an 8 came after it)

If you want any other numbers put into 3 significant figures to demonstrate the process, don't hesitate to ask. Hope this helps.

Edited April 27, 2013 by TykeDragon

[carpediem]

But there's a pre loaded APP on the Texas Calculator that converts your answer into significant figures. Scroll down to Sci Tools and its the first one: Sig-Fig Calculator.

Even if you do change the settings, don't you have to wipe the memory of the calculator prior to the exam anyway?

[Yahooo!]

Yes but it's a pre loaded app, so it's one that remains

[onur basman]

even if you don't have that app my GDC (ti Nspire ) has an option in the settings which you can easily change during the exam. On the long run it could be easier to do it in your head as TykeDragon mentioned earlier

[susanne]

3 sig figs, always 3, unless questions specify otherwise