DO NOW

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 Figs Taking Uncertainty to the Next Level (Turn down for what?)

3. Significant Figures in Measurement • The 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 4 5.6 ft2 65.6 lb___ 122.55 m ___ Complete: All non-zero digits in a measured number are (significant or not significant). 3 5

5. Leading Zeros Number of Significant Figures 0.008 mm 1 0.0156 oz3 0.0042 lb____ 0.000262 mL ____ Complete: Leading zeros in decimal numbers are (significant or not significant). 2 3

6. Sandwiched Zeros Number 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 yr1 48,600 gal 3 25,005,000 g ____ Complete: Trailing zeros in numbers without decimalsare (significant or not significant) if they are serving as place holders. 5

8. Learning Check In 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 Check State 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 1032) 25.300 3) 0.00307 C. 534,675 rounded to 3 significant figures is 1) 535 2) 535,000 3) 5.35 x 105 4 3 3

11. Independent Practice • Worksheet • Work alone or with a partner • Perfect time for questions

12. Significant Figures in Calculations & Rounding Unit 1: Measurement & Matter

13. Rounding w/ Sig Figs • COMPUTE answer first!!!! • CHOOSE whether to round based on sig figs or decimal places

14. CALCULATION RULES • For Multiplication & Division limiting term = one w/ the SMALLEST # of sig figs

15. CALCULATION RULES • Multiplication & Division Round answer to the same number of sig figs as the answer with the fewest sig figs

16. Example Round to 6.384 6.4 4.56 x 1.4 = 3 sig figs 2 sig figs 2 sig figs

17. Example Round to 3.702 4 1.234 x 3 = 4 sig figs 1 sig fig 1 sig fig

18. CALCULATION RULES • For Addition & Subtraction limiting term = one w/ the smallest number of DECIMAL PLACES

19. CALCULATION RULES • Addition & Subtraction Round answer to the same number of decimal places as the measurement with the fewest decimal places

20. Significant Figures in Calculations 12.161 + 3.12 = Round to 15.28 • 15.281 3 decimal places 2 decimal places 2 decimal places

21. Significant Figures in Calculations 6.8 + 3 = Round to 10 • 9.8 3 decimal places 0 decimal places 0 decimal places

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

23. You Try…. 8.6 • 2.45 x 3.5 • 8.315 ÷ 298 • 135 x 246 x 0.000556 x 0.0998 x 155 • 3.6x10-3 x 8.123 0.0279 286 0.0068 or 6.8x10-3

24. You Try… • 12.11 + 18.0 + 1.013 = • 29.63 + 24.798 + 1.263 = • 1081 – 7.25 = • 8.445 x 105 – 9.44 x 102 = 31.1 55.69 1074 8.44 x 105

25. Exit Ticket • 16.50 mL – 8.0 mL = • 3.2145 x 4.23 =