Review of Ratios, Proportions, and Percents

Math Response

Convert 46% into a decimal

Type answer here

Correct Answer: .46

Deg^°

Rad

Move the decimal Point

• Always move the decimal 2 spots to the LEFT

Math Response

What is 70% turned into a decimal?

Type answer here

Correct Answer: 0.70

Deg^°

Rad

Multiple Choice

Make the percent to decimal.

7%

• .007

• 0.07

• 7

• 70

Multiple Choice

How would you show 100% as a decimal?

• 1.00

• 0.100

• 0.0100

• 1.11

Math Response

Covert 130% to a decimal.

Type answer here

Correct Answer: 1.3

Deg^°

Rad

How do I make my percent proportion?

• Identify if the given quantity is a PART or a WHOLE amount

• % is always out of 100, so this means " % / 100% "

Poll

Optometrists estimate that up to 75% of adults wear eyeglasses or contacts. In a lecture hall, 50 college students are wearing either glasses or contacts. About how many students are in the hall?

RESPOND TO THIS: WHAT TYPE OF PROBLEM ARE YOU SOLVING? WHAT'S THE MISSING PIECE OF INFORMATION?

• PART

• WHOLE

• A PERCENT

Multiple Choice

Identify what you are solving for in this situation: 20% of students in class are wearing red. There are 30 students in the class. How many are wearing red?

• Finding the part

• Finding the whole

• Finding a percent

Multiple Choice

Identify what you are solving for in this situation: Five out of 10 cake slices have been eaten. What percent of the cake was eaten?

• Finding the part

• Finding the whole

• Finding the percent

Multiple Choice

Identify what you are solving for in this situation: 300 students have pets that attend school. If 30% of all students have pets, how many students are there in the school?

• finding the part

• finding the whole

• finding the percent

How do you solve for a percent?

• Write out your % Proportion: part/whole = % / 100%

• Scale up or down as necessary

Multiple Choice

Which of these is set up correctly for "30 is what percent of 600"?

Multiple Choice

Which of these is set up correctly for "What percent of 55 is 80"?

1. Cross Multiple & Divide

2. Scaling Up or Down

​Solving

Math Response

What is 9% of 200?

Type answer here

Correct Answer: 18

Deg^°

Rad

Math Response

What is 30% of 80?

Type answer here

Correct Answer: 24

Deg^°

Rad

Math Response

29 out of 50 is what percent ?

________%

Type answer here

Correct Answer: 58

Deg^°

Rad

PERCENT EQUATIONS

​

​Part = Whole x Percent in Decimal Form

​

​

  The part is equal to the percent multiplied by the whole, when the percent is in fraction or decimal form.

​

​

​

​56

​Now solve the one step equation

​56 is what percent of 95

​=

​x

​*

​95

Math Response

27 is what percent of 138?

(round to nearest whole percent)

______%

Type answer here

Correct Answer: 20

Deg^°

Rad

​18

​Now solve the one step equation

​18 is 25% of what number

​=

​x

​*

0.25

Math Response

22 is 31% of what number?

(round to the nearest tenth)

Type answer here

Correct Answer: 7

Deg^°

Rad

Poll

In your opinion, which method is easier to solve percents?

• Percent Proportion $$\frac{part}{whole}=\frac{\%}{100}$$

• Percent Equation $$part\ =\ whole\ \times\ \%$$ $$\%\ =\ \frac{part}{whole}$$ $$whole\ =\ \frac{part}{\%}$$

Percent Increase and Decrease

Definitions

• Percent Change--the percent by which a number increases or decreases.

• Percent Increase--the percent change that describes an increase in a quantity

• Percent Decrease--the percent change that describes an decrease in a quantity

Multiple Choice

How does the number change?

(Cómo cambia el número?)

304 ----> 322

• Increase

• Decrease

• Neither (ninguno)

Multiple Choice

How does the number change?

(Cómo cambia el número?)

625 ----> 590

• Increase

• Decrease

• Neither (ninguno)

When you get to the checkout you need to pay 8% sales tax. What is the total percentage?

ANSWER: 108%

Example:

Increase means you have more than 100%. Therefore you will add 100% to your percentage to find the total percent

Percent increase

What to do with a percent change?

Math Response

You want to leave a 20% tip for your waitress. What is the total percentage you will pay?

_______%

Type answer here

Correct Answer: 120

Deg^°

Rad

You have a 20% off coupon. What is the total percentage you will pay?

ANSWER: 80%

Example:

A percent decrease is when you made less than all of your expected amount. Therefor you will subtract the percent from 100% to get your total percentage.

Percent decrease

What to do with a percent change

Math Response

At Old Navy everything is 25% off. What percentage will you pay?

__________%

Type answer here

Correct Answer: 7

Deg^°

Rad

Multiple Choice

What is the correct Percent Change equation? 

Percent of change = _____

• $$\ \frac{original\ amount}{amount\ of\ change}$$  

• $$\ \frac{percent\ change}{original\ amount}$$  

• $$\ \frac{amount\ of\ change}{original\ amount}$$  

• $$\ \frac{original\ amount}{percent\ of\ change}$$  

Multiple Choice

If you have a percent increase problem, your original amount:

• Gets bigger

• Gets smaller

• Doesn't change

• Stays the same

Multiple Choice

1. Find the PERCENT of change.

20 dogs to 5 dogs

• Decrease 15%

• Increase 15%

• Increase 75%

• Decrease 75%

Multiple Choice

2. Find the PERCENT of Change.

The original cost was $50 and the new cost is $60.

• Increase 20%

• Increase 16.67%

• Increase $10

• Decrease $10

Multiple Choice

3. Find the percent of change if Eddie started with 20 tickets and ended with 30 tickets.

• Increase 10 tickets

• Increase 50%

• Increase 33%

• Decrease 50%

Multiple Choice

What is the percent of change? 55 mph to 70 mph

• 27% increase

• 27% decrease

• 21% increase

• 21% decrease

How did you do that?

Math Response

What is the percent of change? 92 lb to 200 lb

______ % Increase

Type answer here

Correct Answer: 117

Deg^°

Rad

Multiple Choice

What is the percent of change? 70 mph to 55 mph

• 21% decrease

• 21% increase

• 27% increase

• 27% decrease

Simple Interest

Standard: 7.RP.3

Use scale factors and unit rates in proportional relationships to solve ratio and percent problems.

I can solve problems with simple interest.

Simple Interest

• I=Prt

• I=Interest, P=Principal, r=Rate as a decimal, T=Time in years

Multiple Choice

The simple interest formula is I=Prt.  The P represents the principal.  The principal is ___________________.  

• the amount of money borrowed or deposited

• the percent interest for his year

• the amount taxed

• the amount the bank owes you for being a customer at their bank

Multiple Choice

The rate is given as a percent (%).  Before using it in the simple interest formula, you must first convert it to a______.

• fraction

• decimal

• ratio

• dollar amount

If your "t" isn't given to you in years, convert it.

• days = divide by 365 (leap years don't really count in finance)

• weeks = divide by 52

• months = divide by 12

Multiple Choice

If you are calculating the simple interest and you are given the time in months, how can you find the time in years?

• Add 12 to the months

• divide the months by 12

• multiply 12 times the months

• You cannot change it to months.

Multiple Choice

Convert 18 months to years. 

• 18 Years

• 1.5 Years

• .18 Years

• You cannot change it to years.

Multiple Choice

Write the percent as a decimal. 
4.3%

• 4.3

• .43

• .043

• 4300

Multiple Choice

Principal = $500
Interest rate =5%
Time = 5 years
What is the interest earned?

• 95

• 105

• 125

• 135

Multiple Choice

What is the formula for simple interest?

• T = pri

• I = prt

• R = ipt

• P = irt

Multiple Choice

Starting money = $350.
Interest rate = 2.5%
TIme = 3 years.
How much interest?

• $7.50

• $26.25

• $87.5

• $262.50

Multiple Choice

Emilio borrows $1200 from a bank with 8% simple interest per year.  How much will he have to pay back total in 2 years?

• $150

• $192

• $1350

• $1392