1. BR: When? Why? When do we use scientific notation?
Why are significant figures important?
Scientific notation is used to express numbers that are very large or very small.
SN allows us to shorten the number.
SFs allow us to be precise – even when our instruments limit precision.

2. Practice BEFORE you submit
Scientific Notation
Math Handbook p
#1-3, p948
Significant Figures
Math Handbook p
#4, p951
#5-6, p953
Submit 3 topic worksheets
(may only be two pieces of paper)
DUE today or tomorrow – NO PENALTY

3. How wide is our universe?
210,000,000,000,000,000,000,000 miles
(22 zeros)
This number is written in decimal notation. When numbers get this large, it is easier to write them in scientific notation.

4. A number is expressed in scientific notation when it is in the form
a x 10n
where a is between 1 and 10
and n is an integer

5. Write the width of the universe in scientific notation.
210,000,000,000,000,000,000,000 miles
Where is the decimal point now?
After the last zero.
Where would you put the decimal to make this number be between 1 and 10?
Between the 2 and the 1

6. 2.10,000,000,000,000,000,000,000.
How many decimal places did you move the decimal? 23
When the original number is more than 1, the exponent is positive.
The answer in scientific notation is
2.1 x 1023

7. 1) Express 0.0000000902 in scientific notation.
Where would the decimal go to make the number be between 1 and 10?
9.02
The decimal was moved how many places? 8
When the original number is less than 1, the exponent is negative.
9.02 x 10-8

8. Write 28750.9 in scientific notation.
x 10-5
x 10-4
x 104
x 105

9. 2) Express 1.8 x 10-4 in decimal notation.
3) Express 4.58 x 106 in decimal notation.
4,580,000
On the graphing calculator, scientific notation is done with the button.
4.58 x 106 is typed

10. 4) Use a calculator to evaluate: 4.5 x 10-5 1.6 x 10-2
Type
You must include parentheses if you don’t use those buttons!!
(4.5 x ) (1.6 x )
Write in scientific notation.
x 10-3

11. 5) Use a calculator to evaluate:. 7. 2 x 10-9. 1
5) Use a calculator to evaluate: x x 102 On the calculator, the answer is:
6.E -11
The answer in scientific notation is
6 x
The answer in decimal notation is

12. 6) Use a calculator to evaluate (0. 0042)(330,000)
6) Use a calculator to evaluate (0.0042)(330,000). On the calculator, the answer is
1386.
The answer in decimal notation is
1386
The answer in scientific notation is
1.386 x 103

13. 7) Use a calculator to evaluate (3,600,000,000)(23)
7) Use a calculator to evaluate (3,600,000,000)(23). On the calculator, the answer is:
8.28 E +10
The answer in scientific notation is
8.28 x 10 10
The answer in decimal notation is
82,800,000,000

14. Write (2.8 x 103)(5.1 x 10-7) in scientific notation.

15. Write in PROPER scientific notation
Write in PROPER scientific notation. (Notice the number is not between 1 and 10) 8) x 109
2.346 x 1011
9) x 104
on calculator: 642
6.42 x 10 2

16. Write 531.42 x 105 in scientific notation.

17. Sig Figs

18. #5 influence when rounding:
Sig Fig Rules
Addition or Subtraction
Procedure to determine significant figures after adding or subtracting:
1. Add or subtract the numbers on your calculator (or by hand).
2. Round the result to the same number of decimal places as the least precise value.
Multiplication or Division
Procedure for significant figures after multiplication or division:
1. Multiply or divide the numbers using your calculator.
2. Round the result to have the same number of significant figures as the measured value with the least number of significant figures.
#5 influence when rounding:
Even stay the same
Odd round up or down