1. Happy Birthday to Niels Bohr (1885)
Reading:
Chapter 2 sections 5-8

2. Sig. Figs. in Calculations
Two rules:
#1) Multiplication and Division
The value in the calculation that has the FEWEST number of sig. figs. determines the number of sig. figs. in your answer.

3. Calculations with Sig. Figs.
Multiplication and division
The value in the calculation that has the FEWEST number of sig. figs. determines the number of sig. figs. in your answer.
1.5 x
= 1
.9891
= 11
2 s.f.
5 s.f.
6.127 x ( x10-5) = 6 09 =
4 s.f.
6 s.f.

4. Sig. Figs. in Calculations
Two rules:
#1) Multiplication and Division
The value in the calculation that has the FEWEST number of sig. figs. determines the number of sig. figs. in your answer.

5. Calculations with Sig. Figs.
/ 456.0
= 2.03 3
730263
= 2.034
6 s.f.
4 s.f.
/ 2
= 0.000 7 95 =
3 s.f.
1 s.f.
6 s.f.
3 s.f.
= 18 8
= x107
4 s.f.
= 1.89x107

6. Some Practice
x 112.3
78132/2.50
x x
500 x
99950 or 9.995x104
31300 or 3.13x104
0.0050
2.5x10-8
1.9x106
0.1

7. Sig. Figs. in Calculations
Two rules:
#1) Multiplication and Division:
The value in the calculation that has the FEWEST number of sig. figs. determines the number of sig. figs. in your answer.
#2) Addition and Subtraction:
The value in the calculation that has the FEWEST decimal spots determines the number of decimal spots in your answer.

8. Adding and subtracting with sig. figs.
7 decimal places
6 decimal places _ _ =
answer can only
be precise to the
6th decimal place

9. Adding and subtracting with sig. figs.
4 decimal places
7 decimal places =
answer can only
have 4 decimal places

10. Adding and subtracting with sig. figs.
0.01 –
2 decimal places
6 decimal places
0.01
0.01 – –
= 0.00
answer can only
be precise to the
2nd decimal place

11. Adding and subtracting with sig. figs.
no decimal
places
2 decimal places
682377
682377 =
x105
answer can only
be precise to the
ones place

12. Some More Practice 23.67 – 75 5502.8 + 24 + 0.01 0.109 + 0.09 – 0.955
-51
5527
-0.76
100.
61690 or 6.169x104