1. -why we use them -rules for sig. figs. -operations with sig. figs
Significant Figures
                  
                  
                
                        
                      
                  
                  
-why we use them
-rules for sig. figs.
-operations with sig. figs

2. What are Significant Figures?
They are all the numbers in a measurement that are known with certainty plus the first digit that is uncertain.

3. Why use Significant Figures?
Significant figures are needed in science, because the tools we use to measure are not infinitely accurate.
How accurate is a:
Meter stick
Electronic balance
Graduated cylinder

4. SIDENOTE: You will hear significant figures also called:
Significant digits
Sig figs

5. Significant Figure Rules
1) All non-zero digits are significant.
How many significant figures are in the number ?

6. 2) All zeros that are between two non-zero digits are significant.
Captive zeros
2) All zeros that are between two non-zero digits are significant.
How many significant figures are in the number 28,005?

7. 3) Zeros to the right of a non-zero count only if there is a decimal .
Trailing Zeros
3) Zeros to the right of a non-zero count only if there is a decimal .
How many significant figures are in the number 23,000?
How many significant figures are in the number 80.0?

8. Leading Zeros
4) All zeros in front of non-zero digits are NOT significant (includes to the right and left of the decimal)
How many significant figures are in the number ?

9. How many SIGNIFICANT FIGURES are in the following numbers?

10. 83.591

11. 5007

12. 10.005

13. 20 080

15. 0.0012

16. 1.007

17. 196.0

18. 75000.

19. 1.52x10 22

20. 2.00x10-6

21. Multiplying/Dividing with Sig Figs
Answer should have the same #
sig figs as the quantity with the least # of sig figs.
What is x 11.7?

22. Adding/Subtracting with Sig Figs
Answer should have the same # of decimal places as the quantity with the least # of decimal places.
What is ?

23. Do the following problems with the correct number of SIGNIFICANT FIGURES.

24. 24 x 31.8

25. 8.4/4.2

26. 49.1 – 8.001

28. x 3.227

29. 1007/33.6

30. 20300 –

31. 1.005 – 3.60

32. 76.00 x 13

33. 1.5x1021 x 2.07x1013

34. 1.8x106/2.77x1019

35. Rounding What is 44.4? What is 67.5?
If the last decimal is below 5, round down
If the last digit is 5 or above, round up
What is 44.4?
What is 67.5?