1. Significant Figures or Digits
Take notes, this is important!

2. What are Significant Digits?
The Important Numbers
Representatives of the precision and accuracy of measurements.
Absolutely Necessary!

3. Why Do We Have Significant Digits?
They limit the number of decimal places
They give our calculations relevance
They make students crazy

4. Identifying Significant digits
A SigFig is:
All nonzero numbers
Leading zero non significant
Captive zeros (zeros in between nonzero numbers)
Trailing zeros when a decimal is present

5. Identifying Significant Digits
A SigFig is not:
Leading zeros
Trailing zeros when there is no decimal

6. Trailing - If a decimal is present
Are Zeros Significant?
Trailing - If a decimal is present
Leading – Never
Captive – Always

7. Identifying Significant Digits
12, All are SigFigs
1,234, SigFigs
SigFigs
1,020,304 All are SigFigs
SigFigs
1.230 x SigFigs
SigFigs

8. Using Significant Digits
Adding and Subtracting - The final calculated answer should have the same # of decimal places as the measurement that is the least accurate (least # of decimal places).
Multiplying and Dividing- The final calculated answer should have the same # of SigFigs as measurement with least # of Sig Figs.

9. Rounding Rules
If a digit is to be cut off, and it is less than 5, the # before the cut remains the same.
If a digit is to be cut off, and it is greater than or equal to 5, then the # before the cutoff is increased by 1.
Always wait to round #’s until the last calculation is completed.