1. Measurement
Accuracy & Precision

2. Accuracy
How close a measurement is to the actual value

3. Precision
How close a series of measurements are to each other o

4. Significant figures
We get sig figs from the idea that we can only be a precise as our least precise measurement.
Basically, sig figs tell us how Exact our numbers are!

5. Rules for identifying sig figs
All NON-zero digits are significant
All zeros between 2 non-zero digits are significant
Zeroes to left of understood decimal point are NOT SIGNIFICANT!
Ex) (4 SF’s) Ex) 2002 (4 SF’s) Ex) (5 SF’s) Ex) 1200 (2 sig figs)

6. Sig figs (cont) 200. (3 SF’s) 12320. (5 SF’s) 0.00045 (2 SF’s)
4. All zeros to the left of a expressed decimal point are significant if number is greater than 1
5. All zeros to right of a decimal point, but left of non-zero digit are NOT SIGNIFICANT! (if number is less than 1)
(3 SF’s)
(5 SF’s)
(2 SF’s)
0.01 (1 SF)

7. Sig figs (cont) 0.0300 (3 SF’s) 0.02000 (4 SF’s)
6. All zeros to right of decimal and right of non zero digit are significant
(3 SF’s)
(4 SF’s)

8. Sig figs (cont) Ex) 5.334 X 103 (4 SF’s) Ex) 3.00 X 10-5 (3 SF’s)
7. All digits expressed in front of power of 10 in Scientific Notation are significant.
Ex) X 103 (4 SF’s) Ex) 3.00 X 10-5 (3 SF’s)

9. Identifying Practice 5.550 g 100 hs 3450 dg 0.000023404 cg 7.650 mm
400. L
das
3.45 X 1012 kg
9.240 X 10-2 cs

10. Identifying Extra Practice
7.00
0.001
400
.00340
4.56 X 104
1200.

11. Rounding For each of the following numbers, round to 3 sig figscm
1367 dg
128,522 kL
106 mm
1.56 m cm
1370 dg kL
1.67 X 106 mm

12. Rounding Extra Practice
4500 cs (1)
dg (3)
mm (2)
kg (2)
g (5)
12890 hg (2)
ms (1)
kL (4)
5000 cs
39000 dg mm kg g
13000 hg ms
130.0 kL

13. S.F. Multiplication/Division
Answer can only have the same quantity of sig figs as the least significant number used in the calculation
Ex:)
5.33 X 1.2 = 6.396
* Answer can only have 2 S.F.’s, so the answer must be rounded to 6.4

14. Multiplication/Division Practice
Complete the following:
38 g  22.4 g
48.3 mm / 12.0 mm
3.47 cm / 40 cm
428.3 mL  2.4 mL
850 g
4.03 mm
0.09 cm
1000 mL

15. Addition & Subtraction
2 D.P.
FOCUS ON DECIMAL PLACES!! The answer can only have the same number of decimal places as the number used to obtain it with the fewest decimal places
35.09
(Answer can only have 2 D.P)
In sig figs=
35.33
4 D.P.

16. Problems 22.3 cm + 3.45 cm 7.2 s + 15 s 6.0 kg – 5.34 kg
48 m – m
25.8 cm
22 s
0.7 kg
48 m