You need to know how to do these withOUT your Calculator

Warm-up

Find each percent to the nearest tenth.

1. What percent of 33 is 22?

2. What percent of 300 is 120?

3. 18 is what percent of 25?

4. The volume of Lake Superior is 2900 mi3 and

the volume of Lake Erie is 116 mi3. What percent

of the volume of Lake Superior is the volume of

Lake Erie?

40%

66.7%

72%

4%

REG. $14.99

@ 20% off

Tax = 7.2%

REG. $14.99

@ 30% off

Tax = 8.2%

REG. $8.88

@ 15% off

Tax = 5.25%

Percent Increase and Decrease!

8-7

When a number changes, you can use a percent

increase or percent decrease to describe the

size of the change. A percent increase or

decrease is always based on the original amount!Percent of Change

= 100

Amount of Change

Original Amount

Solving the proportion:

Is one way to find % change!

Percent of Change

= 100

Amount of Change Original Amount

The number of students who got straight A’s decreased from 612 to 450 in one year! Find

the percentage of decrease!

P -Percent of Change

= 100

162

612

P -Percent of Change

= 100

162

612

612p = 100 162

612p = 16,200

612p 612 = 16,200 612

p = 26.47

p 26.5

Kevin shot 47 times on Saturday. On Monday, he shot 57% less than he did on

Saturday.

How many times did he shoot on Monday!

Kevin shot 13 times on Saturday. On Monday, he shot 18 times…

What is the percent

of increase?

You earned $15 babysitting last week. This week you only earned $12…

What is the percent

of decrease?

You took off your shoes and made five people leave the room. Your teacher took off her shoes and made 14 people leave the room.

How many more people left when your teacher

took off her shoes? Express your answers as

a percent!

Reg. $49.99

Save 20%

Marcus wants to see the world!

How much would it cost?

$39.99

When stores, round, they always round up!

$2.991 we know as $2.99, but stores would mark it as $3.00.

Doesn’t sound like such a big deal? If they do this with each person in the country, it would

be 3,500,000 per day!

“Sales Tax” is an additional “fee” placed on items purchased. This fee goes to city, county, state and even the federal government to pay for financial needs. “Sales Tax” varies from city to city.

We’ll use 7.5% as our sales tax.

Reg. $19.99

Now Free

Now you can own a Yankee Hat of your very

own!

Nobody wants one!

Reg. $49.99

Save 20%how much $ after taxes?

$42.99

Colby wants to see the world!

Reg. $34.88

Save 25%

Get Ben A Dart Board for his Birthday!

How much $ after taxes?

$28.13

The number of people enlisting in the U.S. Army increased by 12% in October, 2001. In September, 24,000 people enlisted.

26, 880

How many people enlisted in October?

7-8

1. A bank is offering 2.5% simple interest on a savings account. If you deposit $5000, how much interest will you earn in one year?

2. Joshua borrowed $1000 from his friend and paid him back $1050 in six months. What simple annual interest did Joshua pay his friend? 10%

$125

7-8

3. The Hemmings borrowed $3000 for home improvements. They repaid the loan and $600 in simple interest four years later. What simple annual interest rate did they pay?

4. Mr. Berry had $120,000 in a retirement account. The account paid 4.25% simple interest. How much money was in the account at the end of 10 years?

5%

$171,000

Lesson Quiz: Part 2

3. The Hemmings borrowed $3000 for home improvements. They repaid the loan and $600 in simple interest four years later. What simple annual interest rate did they pay?

4. Mr. Berry had $120,000 in a retirement account. The account paid 4.25% simple interest. How much money was in the account at the end of 10 years?

5%

$171,000

REVIEW - Warm Up

1. What is 35 increased by 8%?

2. What is the percent of decrease from 144 to 120?

3. What is 1500 decreased by 75%?

4. What is the percent of increase from 0.32 to 0.64?

37.8

375

100%

16 %2

3

If: A B C D E F G H I J K L M N O P Q R S T U V W X Y Z is represented as:

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26.

Then:

H-A-R-D-W-O-R-K 8+1+18+4+23+15+18+11 = 98%

and K-N-O-W-L-E-D-G-E

11+14+15+23+12+5+4+7+5 = 96%

But,

A-T-T-I-T-U-D-E 1+20+20+9+20+21+4+5 = 100%

Homework

• Study Guide and Review…ALL– Pg 438 #s1-31

– Know how to do these withOUT your Calculator.