We learned the basics of factors and multiples....

Let's check your understanding!

Now, let's do some ACT practice problems with Factors and Multiples...

Ratios, Proportions and Percents

Vocabulary

RATIO:  a comparison of two or more values
PROPORTION:  a statement where two or more ratios are equal 
PERCENT:  a number or ratio expressed as a fraction of 100.  Percent means per hundred.

Let's learn a strategy...

Percents:
We can easily find 1% and 10% of any number in our heads!

Let's start with the number 800.

Find 1% of 800:

Find 10% of 800:

Now let's find 1% and 10% of 6.235.

Find 1% of 6.235:

Find 10% of 6.235:

Let's do this problem 2 different ways...
First by finding 1% and 10% mentally.

To keep up with rising expenses, a motel manager

needs to raise the $40.00 room rate by 22%. What will be the new rate?

F. $40.22

G. $42.20

H. $48.00

J. $48.80

K. $62.00

Let's do this problem 2 different ways...
Second by using the calculator.

To keep up with rising expenses, a motel manager

needs to raise the $40.00 room rate by 22%. What will be the new rate?

F. $40.22

G. $42.20

H. $48.00

J. $48.80

K. $62.00

Get ready to practice an example!

Ratios
A comparison of two or more values.

Can be represented several ways....

Let's learn a strategy...

Ratios and Proportions: Bar Model/Tape Diagram
Sketching a quick bar model can make ratios easier.  Let’s look at an example:
David and Jason have marbles in a ratio of 2:3.  Together, they have 35 marbles.  How many marbles does each boy have?

David

Jason

Proportions

A proportion is an equation stating that two ratios are equivalent.

In other words, two sets of numbers are proportional if one set is 

a constant times the other.

Recall:   In a proportion, the cross products are equal.