Calculators and significant figures

In summary, significant figures are important because they indicate the precision and accuracy of a measurement. To determine the number of significant figures, count from the first non-zero digit from the left, and remember that zeros may or may not be significant. When rounding a number to the correct number of significant figures, identify the last significant figure and round accordingly. Significant figures can be used in addition and subtraction calculations, with the final answer having the same number of decimal places as the number with the fewest decimal places in the calculation. In multiplication and division calculations, the final answer should have the same number of significant figures as the number with the fewest significant figures, and the final answer should be rounded to the correct number of significant figures.
  • #1
fisico30
374
0
Dear Forum,

why do calculators always give an incorrect number of significant figures?
What assumptions do they make?

thanks
fisico30
 
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  • #2
fisico30 said:
Dear Forum,

why do calculators always give an incorrect number of significant figures?
I don't believe that the concept of significant figures enters into things at all. A calculator will either give you an exact result (e.g., 2 * 5 = 10, .02 * .04 = .008) or will produce a result with as many decimal places as it is able to display.
fisico30 said:
What assumptions do they make?

thanks
fisico30
 

FAQ: Calculators and significant figures

1. What are significant figures and why are they important?

Significant figures are the digits in a number that represent the precision of a measurement. They are important because they indicate the level of accuracy of a measurement and help to ensure the correct number of digits are used in calculations.

2. How do I determine the number of significant figures in a number?

To determine the number of significant figures, start counting from the first non-zero digit from the left. All non-zero digits are significant. Zeros between non-zero digits are also significant. Zeros at the beginning of a number are not significant. Zeros at the end of a number are only significant if there is a decimal point present.

3. How do I round a number to the correct number of significant figures?

To round a number to the correct number of significant figures, start by identifying the last significant figure. If the next digit is 5 or above, round up the last significant figure. If the next digit is less than 5, leave the last significant figure as it is. Remember to replace all digits to the right of the last significant figure with zeros.

4. Can I use significant figures in addition and subtraction calculations?

Yes, you can use significant figures in addition and subtraction calculations. The final answer should have the same number of decimal places as the number with the fewest decimal places in the calculation.

5. How do I use significant figures in multiplication and division calculations?

When multiplying or dividing numbers, the final answer should have the same number of significant figures as the number with the fewest significant figures in the calculation. Remember to round the final answer to the correct number of significant figures.

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