In the mall parking lot, 60% of the cars are blue. If there are 300 cars in the

parking lot, how many are blue?

In this lesson you will learn to calculate the part when you

know the percent and the total by using a double number line.

Let’s Review

A percent is a part-to-total ratio where the second number is always 100.

60% = 60 percent = 60 for every 100

Let’s Review

5 ways to solve a ratio problem

1) Table with addition2) Table with multiplication3) Double number lines4) Tape diagrams5) Graphing

Let’s ReviewA Common Mistake

Thinking that a ratio describes just one situation

Example: 1 pink sweater for every 5 sweaters

1 out of 5 is pink.

2 out of 10 are pink.

3 out of 15 are pink.

Let’s ReviewCore Lesson

KNOW

In the mall parking lot, 60% of the cars are blue. If there are 300 cars in the parking lot, how many are blue?

Percent:

CALCULATE

60 for every 100 cars are blue.Total: 300 cars

Part: ??? blue cars

Let’s ReviewCore Lesson

blue cars

total cars

0

0

60

100

120

200

180

300

Total: 300 cars

CALCULATE Part: 180 blue cars

KNOW Percent: 60 for every 100 carsare blue.

Let’s ReviewCore Lesson

blue cars

total cars

0

0

60

100

120

200

x3

x3

180

300

In this lesson you have learned to calculate the part when you know the percent and the total by using a double number line.

Let’s ReviewGuided Practice

Nick has 20 baseball cards. 40% of his cards are players on the Washington Nationals team. How many of his cards are Nationals players?

Let’s ReviewGuided Practice

Let’s ReviewExtension Activities

Rewrite the example problem from this lesson so that the answer is 240 blue cars. See if you can find more than one way to rewrite the problem.

Let’s ReviewExtension Activities

In the mall parking lot, 60% of the cars are blue. If there are 450 cars in the parking lot, how many are blue?

Let’s ReviewExtension Activities

In the library, 25% of the books are non-fiction. If there are 200 books in the library, how many are non-fiction books?

Let’s ReviewQuick Quiz

Paul had $500 in his savings account. He spent 25% of his savings on a new bike. How much money did he spend on the bike?

There are 50 cars parked in the lot outside the movie theater. 20% of the cars are red. How many red cars are in the parking lot?