1

DO NOW Round to the nearest tenth:

7.16 5.54 8.66 2.65 3.469 7.673

Round to the nearest hundred:861 436 3979 1873 6758 1555

2

Sig FigsTaking Uncertainty to

the Next Level

(Turn down for what?)

3

Significant Figures in MeasurementThe numbers reported in a

measurement are limited by the measuring tool

Significant figures in a measurement include the known digits plus one estimated digit

4

Counting Significant Figures

Number of Significant Figures

38.15 cm 45.6 ft 265.6 lb ___122.55 m ___

Complete: All non-zero digits in a measured number are

(significant or not significant).

5

3

5

Leading Zeros

Number of Significant Figures

0.008 mm 1

0.0156 oz 3

0.0042 lb ____

0.000262 mL ____

Complete: Leading zeros in decimal

numbers are (significant or not significant).

3

2

6

Sandwiched ZerosNumber of Significant

Figures

50.8 mm 3

2001 min 4

0.702 lb ____

0.00405 m ____

Complete: Zeros between nonzero numbers are (significant or not significant).

3

3

7

Trailing Zeros Number of Significant Figures

25,000 in. 2

200 yr 1

48,600 gal 3

25,005,000 g ____ Complete: Trailing zeros in numbers

without decimals are (significant or not significant) if they

are serving as place holders.

5

8

Learning CheckIn which set(s) do both numbers contain the same number of significant figures?

1) 22.0 and 22.00

2) 400.0 and 40

3) 0.000015 and 150,000

9

Learning CheckState the number of significant figures in each of the following:

A. 0.030 m 1 2 3

B. 4.050 L 2 3 4

C. 0.0008 g 1 2 4

D. 3.00 m 1 2 3

E. 2,080,000 bees 3 5

7

10

Learning Check

A. Which answers contain 3 significant figures?1) 0.4760 2) 0.00476 3) 4760

B. All the zeros are significant in

1) 2.050 x 103 2) 25.300 3) 0.00307C. 534,675 rounded to 3 significant

figures is

1) 535 2) 535,000 3) 5.35 x 105

4 33

11

Independent Practice Worksheet

Work alone or with a partner

Perfect time for questions

Significant Figures in Calculations & RoundingUnit 1: Measurement & Matter

1. COMPUTE answer first!!!!

2. CHOOSE whether to round based on sig figs or decimal places

Rounding w/ Sig Figs

CALCULATION RULES

For Multiplication & Division

limiting term = one w/ the SMALLEST # of sig figs

CALCULATION RULES

Multiplication & Division

Round answer to the same number of sig figs as the answer with the fewest sig figs

Example

4.56 x 1.4 = Round to 6.4 3

sig figs

2 sig figs

2 sig figs

6.384

Example

1.234 x 3 = Round to 4 4

sig figs

1 sig fig

1 sig fig

3.702

For Addition & Subtraction

limiting term = one w/ the smallest number of DECIMAL PLACES

CALCULATION RULES

Addition & Subtraction

Round answer to the same number of decimal places as the measurement with the fewest decimal places

CALCULATION RULES

12.161 + 3.12 =

Significant Figures in Calculations

Round to 15.28

3 decimal places

2 decimal places

2 decimal places

15.281

6.8 + 3 =

Significant Figures in Calculations

Round to 10

3 decimal places

0 decimal places

0 decimal places

9.8

22

Summary Only as precise as your “weakest

link” The one w/ fewest sigs figs/decimal

places

Multiplication/ Division-> sigs figs Addition/Subtraction -> decimal

places

1. 2.45 x 3.5

2. 8.315 ÷ 298

3. 135 x 246 x 0.000556 x 0.0998 x 155

4. 3.6x10-3 x 8.123

You Try….

8.6

0.0279286

0.0068 or 6.8x10-3

5. 12.11 + 18.0 + 1.013 =

6. 29.63 + 24.798 + 1.263 =

7. 1081 – 7.25 =

8. 8.445 x 105 – 9.44 x 102 =

You Try…

31.1

55.691074

8.44 x 105

16.50 mL – 8.0 mL =

3.2145 x 4.23 =

Exit Ticket