Download Ratios and Scientific Notation

More Science Skills:
Scientific Notation and Ratios
September 8, 2008
Scientific Notation

Helps you write very large or very small numbers in
an easier way!

Using the power of 10, you can rewrite numbers…

Very small numbers will have a negative notation

Very large umbers will have a positive notation.

For example:

4 X 104 = 40,000

12 X 1012 = 12,000,000,000,000
More examples:
4,650,000 =

4.65 X 106
3 X 10-4 =

.0003
1 X 10-1 =

.1
1.7 X 10-9 =

.0000000017
Let’s Practice:

A. 4.64 X 102

B. 6.43 X 10-6

C. 8.9 X 10-7

D. 4.3 X 106
Writing in Scientific
Notation:
.0032 = 3.2 X 10 -3
1,000000 =

1 X 106
.01 =

1 X 10-2
71,000,000,000 =

7.1 X 1010
Ratios and Proportions

It’s important to know how to use ratios and
proportions when working with different units of
measurement.

The ratio of A to B is written as:

A:B or

A/B
Ratios and Proportions:

RATIO is two (often different) things compared to
each other, or the relationship of 2 numbers.

Proportions show the equality between 2 ratios.

Ex.

3 dollars per gallon.

40 miles per 1 hour.

15 girls versus 14 boys.

23 green balls versus 41 blue balls
Ratios:

Comparing 2 quantities:

A wall is 96 cm high and a pencil is 8 cm long

Divide 8 into 96…it would take 12 pencils to equal
the height of the wall.

Therefore the ratio of the wall to a pencil is

1 to 12

1:12

1/12.
Let’s Practice Ratios:
The ratio of triangles to circles is 3:4, or 3/4
The ratio of triangles to squares is 3:6, or 3/6
The ratios of circles to squares is 4:6, or 4/6
For example:

Last year, 78 girls and 52 boys were enrolled in Earth
Science.

What is the ratio of girls to boys?

Girls : Boys is 78:52, or 78/52

What is the ratio of boys to girls?

Boys : Girls is 52:78, or 52/78
Sample Problem 1:
1. The fish tank is home to 21 sharks. Ratio of males to
females is 3:4.

How many males?

9 Males

How many females?

12 Females
Sample Problem 2
2. Cam’s Pet Shop has 92 rabbits. The ratio is 1:4,
black to white.

How many white?

74

How many black?

18
Sample Problem 3:
3. Farmer Frank raises pigs. He ahs a total of 142 pigs.
The ratio of male to female is 3:4.

How many females?

81

How many males?

61
Sample Problem 4:
4. Mrs. Jonson’s class has 67 students. The ratio is 3 to
2. How many girls were in the class?

How many boys?

27

How many girls?

40