1. 9-1: Relating Fractions, Decimals, and Percents
IWBAT convert a percent to a fraction or decimal and convert a fraction or decimal to a percent.

2. Vocabulary Percent – A special ratio that compares a number with 100
Percent means “per hundred”

3. Fraction to Decimal and Percent
Fraction to Percent
Divide the numerator by the denominator
Put the whole number in front of decimal, if needed
Convert the fraction to a decimal
Move the decimal to the right twice
Add the % sign

4. Examples 1)
2) 3 5 3)

5. Percent to Decimal and Fraction
Percent to Fraction
Remove the % sign
Move the decimal left twice
Remove % sign
Put number over 100
Simplify

6. Examples
1) 15% 2)
3) 120%

7. Decimal to Fraction and Percent
Decimal to Percent
Look at the place value of the fraction
Place decimal over corresponding place value
Simplify
Put whole number in front if there is one
Move decimal right twice
Add the % sign

8. Examples 1) 2) 3)

9. 9-2: Estimating Percent
IWBAT estimate percents of numbers between 0% and 100% using multiples of 10% or fractions

10. Estimating Using Rounding
Round the percent to the nearest 10%
Round the number to the nearest 10s
If the number is less than 10, do not round it
Change the percent to a decimal
Multiply

11. Examples 1) Estimate 28% of 71 2) Estimate 9% of $19.99

12. Estimating Using Fractions
Memorize the following common percent to fraction conversions:
Round the whole number to the nearest 10s
Choose the corresponding fraction
Multiply
10%
20%
25%
33% or 34%
50%
66% or 67%
75%
90%
1 10
1 5
1 4
1 3
1 2
2 3
3 4
9 10

13. Examples 1) 75% of 200 2) 39% of 600 3) 21% of 400 4) 26% of 19

14. 9-3: Finding a Percent of a Number
IWBAT use a proportion to set up percent problems and solve using cross products.

15. Percent Proportion Formula
% 100 = 𝑝𝑎𝑟𝑡(𝑖𝑠) 𝑤ℎ𝑜𝑙𝑒 (𝑜𝑓)
Think of problems as asking, “What is ?”

16. 9-4: Is an Estimate Enough?
IWBAT determine whether an estimate is a sufficient solution or whether an exact amount is needed.

17. 9-5: Mental Math: Finding a Percent of a Number
IWBAT use mental math to calculate percents of numbers

18. Use the same rules as estimating percent

19. 9-6: Solving Percent Problems Using Equations
IWBAT write and solve percent equations.

20. Use the Percent Proportion Formula
% 100 = 𝑝𝑎𝑟𝑡 (𝑖𝑠) 𝑤ℎ𝑜𝑙𝑒 (𝑜𝑓)
Break up the problem and substitute into proper place in proportion formula

21. Write a proportion and solve.
What number is 25% of 62?
1) Break into sections.
What number is
25%
Of 62
= 𝑛 62
2) Substitute into formula
3) Simplify, if possible
4) Cross-Multiply

22. Examples 1) 15 is what percent of 75? 2) What number is 40% of 88?
3) What percent of 90 is 27?
4) What is 120% of 360?
5) 16 is what percent of 40?
6) The 6th grade class is having a book sale. Their order included 300 novels. So far, 180 novels have been sold. What percent of the novels have been sold?

23. IWBAT writ and solve one-step linear equation involving percent
9-7: Write an Equation
IWBAT writ and solve one-step linear equation involving percent

24. IWBAT find sales tax and total cost.
9-8: Finding Sales Tax
IWBAT find sales tax and total cost.

25. Vocabulary
Tip – A percentage of the total of your bill that you give for a service
Tax – A percentage of the total of your bill that you pay to the government

26. Finding Sales Tax and Total Cost
You buy a soccer ball priced at $ If the rate of the sales tax is 6.5%, what is the total cost of the ball?
1) Convert the percent to a decimal
6.5% = 0.065
2) Multiply the decimal by the price. This is the sales tax.
14.69 ∙ 0.065
3) Round UP to the nearest cent
≈ 0.96
4) Add to the price to find the total cost $
$15.65

27. Examples
Find the sales tax and the total cost. Round the sales tax up to the nearest cent.
Cost: $19 Rate of sales tax: 8%
2) Cost: $412 Rate of sales tax: 6%
3) Cost: $62.50 Rate of sales tax: 5.5%
4) A basketball costs $30. The rate of sales tax was 5%. Find the total cost of the basketball.

28. IWBAT find discount and sales price.
9-9: Computing Discount
IWBAT find discount and sales price.

29. Finding the Discount and the Sale Price
The Nature Shop had a 25% sale on kaleidoscopes. Michael bought one originally priced at $ How much did he pay on sale?
1) Convert the percent to a decimal
25% = 0.25
2) Multiply the decimal by the original cost. This is the discount.
15.99 ∙ 0.25
3.9975
3) Round the discount DOWN to the nearest cent.
≈ 3.99
4) Subtract the discount from the original price to find the sale price.
$15.99 – 3.99
$12.00

30. Examples 1) Regular price: $200 Rate of discount: 10%
4) Tommy bought two kaleidoscopes on sale for 20% off. If each kaleidoscope cost $29 before the sale, what did Tommy pay for both on sale?

31. 9-10: Using the Interest Formula
IWBAT use the simple interest formula to calculate interest and find the total amount earned or charged.

32. Vocabulary Interest – the amount of money paid for the use of money
Investments, loans, savings
Interest Formula: I = prt
I is interest
p is principal (original amount deposited or borrowed)
r is the rate of interest (the percent earned or charged)
t is the time the money is in the account or is borrowed (measured in years)

33. Find the interest and total with interest
You put $200 in a savings account earning 5.5% simple interest per year. What is the total you will have in your account after one year?
1) Identify each variable
I = ?
p = $200
r = 5.5% = 0.055
t = 1
2) Rewrite the interest formula
I = prt
3) Substitute. Solve the equation to find interest.
I = prt
I = 200(0.055)(1)
I = $11
4) Add the interest to the principal
$ = $211

34. Find the interest and the total with interest.
Examples
Find the interest and the total with interest.
Principal: $6,000 Rate: 5% Time: 5 months
2) Principal: $4,500 Rate: 18% Time: 6 months
3) Principal: $500 Rate: 7.5% Time: 1 year
4) You want to borrow $500,000 for 6 months at 12% interest. How much money will you owe the bank?