Sig Figs (significant figures) refer to the reliable digits in a measurement. A scientist wants to know which digits in a measurement are reliable. When taking a measurement, one should record digits to one place beyond the precision of the measuring device. For example, a ruler precise to the tenths place requires measurements recorded to the hundredths place, like 8.31. The number of significant figures in a value is based on the digits that are reliable - for example, 1,234,000 has 4 significant figures while 12.30 also has 4 significant figures. Sig figs must be properly handled when adding, subtracting, multiplying and dividing quantities in scientific calculations.

1. Sig Figs
Aka significant figures

2. WHEN A SCIENTIST TAKES A
MEASUREMENT ON SOMETHING
HE/SHE WANTS TO KNOW WHICH
NUMBERS ARE “RELIABLE.” THESE ARE
CALLED SIG FIGS.

3. HOW LONG IS THE BAR NOW?

4. HOW LONG NOW?

5. WHAT IF IT IS RIGHT ON THE
MONEY????? WHAT IS THIS
MEASUREMENT??

6. THIS MEANS THAT THE SCIENTIST IS
SURE OF THE 8, SURE OF THE 3 AND
ALMOST SURE OF THE 1. YOU MAY
ONLY BE UNSURE OF ONE PLACE.
A GOOD RULE OF THUMB IS TO ALWAYS
HAVE NUMBERS TO ONE PLACE
BEYOND THE UNITS GIVEN ON YOUR
RULER OR GRADUATED CYLINDER OR
MEASURING DEVICE.

7. THIS RULER HAS TENTHS SO YOU
SHOULD HAVE VALUES TO THE
HUNDREDTHS PLACE. LIKE 8.31

8. THIS HAS UNITS TO THE NEAREST
WHOLE NUMBER SO REPORT ONE
PLACE PAST THAT --- TO THE TENTHS.
ANSWER IS ????????

9. ?? WHAT IS THE MEASUREMENT?

10. WHAT IS THIS MEASUREMENT
1000
2000
3000

11. WHAT IS THIS MEASUREMENT
1000
2000
3000

12. HOW MANY SIG FIGS IN 2200???
1000
2000
3000

13. HOW MANY SIG FIGS IN 2200???
1000
2000
3000

14. HOW MANY SIG FIGS ARE THERE?
1,234,000 HAS FOUR SIG FIGS.
12.30 HAS FOUR SIG FIGS
0.000045 HAS TWO SIG FIGS, THE
ZEROES ARE SIMPLY THERE TO SHOW
YOU IT’S A SMALL NUMBER.
120000000 HAS TWO SIG FIGS FOR THE
SAME REASON

15. 21.01

16. 102.02

17. 102.02

18. 0.001

19. 1.0100

20. .12345600

21. .000456123

22. 456,123,000

23. 12.78

24. 0.00780

25. 0.007802

26. 0.107802

27. 0.20

28. 10.200

29. 10.002

30. 10200

31. ADDING AND SUBTRACTING AND
MULTIPLYING AND DIVIDING.
With sig figs.

32. 12.3
+ .66

33. 11
+11.1

34. .04
+12.3

35. 7
x1.1

36. 17
x13

37. 1.261
x1