How to round up the numbers in calculation (1 Viewer)

[chopstick]

in the calculations, how do you know where is the number needs to be round up to eg 2 decimal place, 2 significant figures, and when the number needs to be rounded eg molecular weight of H should use 1.008g or just 1g. even the number is round during the calculation, is it better to keep the original number in calculation to get most accurate answer? and if failed to do these, could it lead to loss marks?

 

[Fortify]

Refer to question, if the question shows numbers with 2 sig fig then use 2 sig fig etc etc .

 

[pman]

Refer to question, if the question shows numbers with 2 sig fig then use 2 sig fig etc etc .

.

 

[kwabon]

but do remember this is not the case for pH calculations.
if they are 3 significant figures provided to you in the question, then you have to provide your hydrogen ion concentration to 3 decimal places.

ONLY FOR PH CALCULATIONS, REMEMBER.

 

[brenton1987]

even the number is round during the calculation, is it better to keep the original number in calculation to get most accurate answer? and if failed to do these, could it lead to loss marks?

Do not ever round off in the middle of a calculation.
Give the answer with all of the decimal places and then again to the required number.
If the answer is being used in another calculation use all the decimal places from the first answer.

 

[4lettersdown]

If you have trouble with sig figs, then put it in scientific notation
eg 1000 would only be 1 sig fig as it is 1x10^3
also 0.001 is only 1 because it is 1x10^-3

however 10.00 is four sig figs as it shows how accurate an instrument is.