1. Introduction to Percents

2. Identify Terms Used With Percents
Like a fraction or a decimal, represents part of a whole.
Means hundredths or parts in 100
Symbol is %
25% = 25/100 = 0.25 (25 parts of 100 parts)
33% = 33/100 = 0.33 (33 parts of 100 parts)

3. Write A Percent As A Decimal
Drop percent symbol and divide by 100
35% = 35/100 = 0.35
Drop percent symbol and move decimal point 2 places to the left
35% = 35.0 = 0.35

4. Let’s Try It Convert the following percentages to decimals 1. 27% =
1. 27% =
2. 54% =
3. 49% =
4. 85% =
5. 72% =
6. 12% =
7. 5% =
8. 22%
9. 67% = %

5. Writing Mixed Number Percentages as Decimals
To write a mixed number percent as a decimal
Change the fractional part of the mixed number to a decimal percent.
8 ¼% = 8.25%
Convert decimal percent to its decimal equivalent
Move decimal point 2 places to the left
8.25% =

6. Let’s Try It Convert the following fractional percentages to decimals
Round numbers to the nearest hundredth
/4% =
/5% =
/4% =
/5% =
/5% =
/4% =
/4% =
/5%
/5% =
/5%

7. Common Fractions as Percents
1/5
Convert the fraction to its decimal equivalent
1/5 = ÷ 5 = .20
Convert the decimal to percent
Move decimal point 2 places to the right and add percent symbol
0.20 = 20%

8. Examples To convert fractions to decimals
Percent
5/8 =
0.625
62.5%
3/6
0.5
50%
6/8
0.75
75%
To convert fractions to decimals
divide the numerator by the denominator

9. Let’s Try It
Fraction
Decimal
Percent
1/2 =
1/3
2/3
1/5
2/5
3/5

10. Let’s Try It
Fraction
Decimal
Percent
4/5 =
1/8
3/8
5/8
1/10
5/10
7/10

11. Independent Practice
Complete Worksheet 3.1
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12. Part, Rate and Base

13. Percents are commonly used to determine interest, sales, taxes, commissions, and discounts or to make comparisons

14. Key Terms Base Rate Part Represents 100%
That to which something is being compared
Rate
Number followed by percent symbol
The percent one number is of another one
May be written as decimal of fraction
Part
The number that is a portion of the base

15. As an Equation
Part = Base x Rate
As a proportion IS OF %
100 =

16. For Example What is a 30% discount on a $150 jacket? Equation:
Part = Base x Rate
? = $ x %
Convert to decimal and multiply
$150 x .30 = $45

17. For Example What is a 30% discount on a $150 jacket? Proportion
Cross Multiply X
150 30
100 = IS OF %
100 =
Divide both sides by 100
100X = (30)(150)
100X = 4500
100X = 4500
X = $45

18. Parts with decimals What is 6.5% of 130? Equation Part = Base x Rate
X = x
X =

19. Parts With Decimals What is a 6.5% of 130? Proportion X = 8.45
Cross Multiply X
130
6.5
100 = IS OF %
100 =
Divide both sides by 100
100X = (6.5)(130)
100X = 845
100X = 845
X = 8.45

20. Parts with Fractions
Suppose you had a gain of 6-1/4% on $400. What was the gain?
Change fractional percent to a decimal percent
6.25%
Drop percent symbol and move decimal point to the left two spaces
.0625
Apply formula: Part = Base x Rate
X = $400 x
X = $25
The gain was $25

21. Finding Rate Rate = Part ÷ Base Example: What percent is $15 of $139?

22. For Example What percent is $15 of $139? Proportion X = 10.8
Cross Multiply 15
139 X
100 = IS OF %
100 =
Divide both sides by 139
1500 = 139X
1500 = 139X
X = 10.8

23. Independent Practice
Complete Worksheet 3.2A & 3.2B
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