Percent Review

Percent Review

Percent  %

• Remember the symbol when you write a  percent:  %

• Percent means out of 100

• A percent is a Part-to-Whole comparison

Multiple Choice

20% is equal to 20

• True

• False

Multiple Choice

37% means ...

• 37 out of 1

• 37 out of 10

• 37 out of 100

• 37 out of 1000

A percent can be written as an equivalent fraction or decimal

• Fraction: Put it over 100; simplify if needed.

• Decimal: Move the decimal point two places to the left (Dr. Pepper Backwards). This is dividing by 100.

Multiple Choice

Write 45% as a fraction.

• $\frac{45}{1}$
  

• $\frac{45}{10}$
  

• $\frac{45}{100}$

• $\frac{45}{1000}$

Multiple Choice

Write 63% as its equivalent decimal.

• 63

• 6.3

• 0.63

• 0.063

Multiple Choice

Write 7% as its equivalent decimal.

• 70

• 7

• 0.7

• 0.07

Multiple Select

Choose all that are equivalent to 3%

• 3/10

• 3/100

• 0.03

• 0.3

Calculate the percent of a number

• Convert the percent to its equivalent decimal: Dr. Pepper Backwards

• Multiply (of) by the number

• Example: Find 10.5% of 72

• .105 x 72 = 7.56

Multiple Choice

Find 6% of 12.8

• 768

• 76.8

• 7.68

• 0.768

Multiple Choice

Find 167% of 425

• 70,975

• 7,097.5

• 709.75

• 70.975

Mark-ups and Mark-downs

• Mark-ups are added to the original amount

• Mark-downs are subtracted from the original amount

Multiple Select

Choose all the words which indicate a mark-up.

• Tax

• Tip

• Discount

• Sale

Multiple Select

Choose all the words which indicate a mark-down.

• Tax

• Tip

• Discount

• Sale

Calculate a Mark-Up or Mark-Down

• 1. Find the percent of the mark-up or mark down

• 2. Add or subtract to the original amount as needed

• Example: The check at the restaurant is $17 and you want to leave a 20% tip. What is the total you will pay?

• Step1) .20 x 17 = 3.4

• Step 2) 3.4 + 17 = 20.4

• Answer: $20.40

Multiple Choice

A $50 game is on sale for 45% off. How much will you pay for the game?

• $50

• $45

• $27.50

• $22.50

Using 10% to calculate mental math

• To find 10% of a number, move the decimal point one place to the left

• Example: 10% of 95 is 9.5

• Example: 10% of 8 is 0.8

• Example: 10% of 283 is 28.3

Multiple Choice

What is 10% of 72.4

• 0.724

• 7.24

• 72.4

• 724

10% can help with 5%, 15%, 20%...

• 5% is half of 10%

• 15% is 10% plus 5%

• 20% is twice 10%

• Example: if 10% of 80 is 8 then 5% is 4, 15% is 12, and 20% is 16

Multiple Select

Choose all that are true.

If 10% of 20 is 2 then...

• 20% must be 4

• 20% must be 20

• 5% must be 5

• 5% must be 1

If we are given the part and the whole, we can calculate the percent

• Set up the part-to-whole ratio

• Divide

• Convert the decimal to the equivalent percent

• Example: On a quiz, a student gets 6 out of 10 questions correct.  What percent did the student get correct?

• 6/10 = 0.6 = 60%

Multiple Choice

You answer 38 out of 50 questions correctly. What is the percent you earned?

• 38%

• 12%

• 76%

• 24%

Percent Discount

• Use the Part-to-Whole comparison to calculate the percent paid

• Subtract to calculate the percent discount

• Example: An $80 set of cleats is on clearance for $36. What is the percent discount?

• 36/80 = 0.45 = 45% percent paid

• 100 - 45 = 55% percent discount

Multiple Choice

A $60 video game is on sale for $39. What is the percent discount?

Choose the correct procedure.

• 39/60 = .65

  Answer: 65%

• 39/60 = .65

  100 - 65 = 35

  Answer 35%