Carrying of significant figures

[dekoyl]

I think I've asked this question (or someone has) but can't seem to find the thread with answers in it.
My question is:

How many significant figures should we carry from one (part of a) question to another?
For example, questions will have 1. a) i) ii) iii) etc. and say the required number of significant figures is 2. I give the answer of 1a(ii) to the required significant figure. Then, 1a(iii) will require me to use the answer from 1a(ii). Should I use the final answer of 1a(ii) that has been round of to 2 significant figures or should I use a more accurate one? In Heinemann and NEAP, they seem to use the rounded off one, and so my answer and their answer will differ by a bit.

Thanks! =]

[Edmund]

Dont use the rounded figure.

Use the answer from 1a(ii) with 3 or more significant figures to answer the next part.

[Mao]

Do NOT clear the value off your calculator, always use that for subsequent calculations.

[TrueTears]

Always ALWAYS use the calculations you had for the previous parts to answer the next parts, that way your answers will be as accurate as possible

[pHysiX]

a useful way is to store the answers to the variables on your calc =]

[/0]

Triple J said you can use rounded answers. He showed us a sample examiner's report in which they did it themselves.

[TrueTears]

Triple J said you can use rounded answers. He showed us a sample examiner's report in which they did it themselves.

Who's triple j?

[ed_saifa]

I got this from my uni text


1. For multiplication and division, the result contains the same number of significant figures as the measurement with th fewest significant figures. When the result contains more than the correct number of significant figures, it must be rounded off.

2. For addition and subtraction, the result has the same number of decimal places as the measurement with the fewest decimal places

[/0]

When taking the of a number, the number of significant digits in the log is equal to the number of decimal places in the answer.