When making a calculation, how many significant figures do you use??

Question

please give a good answer and i will love you! thanks :]]

Answer 1

All the answers so far are right.

It's inappropriate to carry through more signficant figures than you have for your worst measurement.

But, you may not want even that many figures, as the more precision you have in a mechanical drawing, the higher the cost.

Answer 2

As many as you can accurately measure. I use more when multiplying the sin of an angle by a large distance, but the final answer is only to the number of significant digits that I am capable of measuring.

Answer 3

As many as the significant figures desired in the answer.

5 x 5 = 25 (20) ,-20%

50 x 50 = 2,500 (2,000) , -33.9%
55 x 55 = 3,025 (3,000) , -0.8%

500 x 500 = 250,000 (200,000) , -35.1%
550 x 550 = 302,555 (300,000) , -2.6%
555 x 555 = 308,025 (308,000) , -.008%

Answer 4

No more than the lowest number of signifigant figures in your data. Possibly one more - for example:

2 / 3 = .6 or possibly .67 not .6666666

2.0 / 3.0 = .67 or possibly .667

zeros after the last digit after decimal point are signifigant.
leading zeros before the first digit after the decimal point are NOT signifigant.

In the examples above, the first your instrument is capable of only measuring to the nearet integer. In the second, you mesaure to the nearest tenth.

Answer 5

If this is for Chemistry, you need to iron out the details with your professor in rounding, because there are two schools of thought on that note.

But teaching significant figures requires more room than what Yahoo! allows, so I'm going to give you UC Berkeley's website tutorial. It will be extremely helpful and less time-consuming.

http://ist-socrates.berkeley.edu/~chem1a/sigfigs/sigfig2.htm

Good luck. If you need help on any problems, I used to tutor Chem and Math, and would love to help.

Answer 6

It depends of the precision needed. For day by day I use two decimals. But if somebody has to calculate something related a very large sum sometimes he´ll need billion digits, for instance to create a security code.

Answer 7

if you're adding or subtracting there can no more significant digits after the decimal point than there are in the number with the least amount of digits after the decimal point. if you're multiplying or dividing there can be no more significant digits than there are in the number with the least amount of significant digits.

Answer 8

That depends entirely on the purpose of the calculation. How much precision do you need?

Answer 9

use no more signfi digits than the 'worst' data item you are using