# Introduction to Percents

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Introduction to Percents

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)

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

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% = %

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% =

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%

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%

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

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

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

Independent Practice Complete Worksheet 3.1 #1 - 40

Part, Rate and Base

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

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

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

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

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

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

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

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

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

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

Independent Practice Complete Worksheet 3.2A & 3.2B #1 - 46