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**Converting Fractions to Decimals**

Two methods: 1. Building a fraction to a base ten number 2. Dividing numerator by denominator

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**Building up the fraction to a base ten number:**

.5 x .20 1.75

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**8/3 : Repeating Decimal = Put a bar over the first**

number(s) that repeats And drop the rest.

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**Mixed Fraction to a Mixed Decimal**

Whole numbers are to the left of the fraction And to the left of the decimal numbers; Convert fractional part to decimal by Dividing

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**Section Understanding Percent**

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**Percent, %, means per hundred.**

The percent number is that number compared to a total of 100. Example: For every $100 invested, you received $6 in return; the interest rate is 6 %

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**What is the percentage for the following:**

386/100 1/100 .07/100 386% 1 % .07%

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Write as a decimal 38% 6% 47% 375% .38 .06 .47 3.75

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**What are the rules to change % to a decimal? Ex: 82%**

Drop the % symbol Perform the operation the symbol represents - Divide by 100 - move decimal 2 places What is the clue word? Per - per hundred means divide by 100

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**Writing a Decimal as a Percent**

Move the decimal point two places to the right – (multiply by 100) 0.47 (100%) = 47 Add the % symbol at the end of the number 47%

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**Which way to move decimal? Remember the alphabet D before P L before R**

52% D P L R .52 .005 D P L R .5%

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**For every 100 total items, there is 47.**

Remember - 47% is 47 out of every A ratio is a comparison BUT You may not have 47 items. For every 100 total items, there is 47. If there were 10 total items, you would have 4.7 items

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**Changing Between Percents, Decimals, and Fractions**

Percent to fraction Drop the symbol Write the percent number over 100 reduce 75% 75 75/100 3/4

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**Example: 225% Rewrite % symbol as 1/100 225 1 __1_ x = 225 100 100**

= 100 100 Simplify (reduce fraction) 2 25/100 = 2 1/4

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**% Example Change to improper fraction Change symbol to fraction %**

Reduce

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**¼ ¾ ½ Memorize the following equivalents 25% 50% 75% 33 1/3% 1/3**

66 2/3% 10% 1/3 2/3 1/10

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Fraction to Percent Can you easily change the denominator to equal 100?

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**If denominator cannot be changed easily **

to 100, find decimal number first. 16.67% Rounded to the nearest Hundredth of a percent

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**Another method – fraction to percent:**

Write a proportion Cross multiply 7*100 = 8 n 700 = 8n Divide by 8 8 8 n = 87.5%

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**Changing a fraction to a percent containing a fraction:**

Stop the division after two steps

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**Solving Percent Problems Using an equation**

Translating a Percent Problem into an Equation

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What is 5% of 19.00? N = .05 x 19.00 N = .95 35% of what is 60? x N = 60 N = 60 / .35 N = Find 0.6% of 400 N = .006 x 400 N = 3.6

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**Words to symbols “What” becomes n “Is” becomes =**

Percent numbers become decimals “of” means multiplication

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**Example 90 is what percent of 20? 90 = p x 20 =4.5 * 100% = 450%**

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**Solving % Problems by using Proportion A = RB**

Identify the Parts of the Percent Proportion The base, b, is always multiplied by the rate. In, 16% of 370, 370 is the base. The amount, a, is always by itself on one side of the equation. In “What percent of 18 is 4.5?”, 4.5 is the amount.

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A, amount Base = b R= percent Rate A = b (R) When solving for percent, change decimal to percent

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**Set up Proportion Cross multiply and then divide**

By the variable’s coefficient Ex: Find 260 % of 40 Reduce fraction and cross multiply A(10)=40( 26) A = 104 A = 4 * 26

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What percent of 4000 is 160? 400 p = 16* 100 4 %

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**END by Lori Tsutsui http://www.numberbasics.com**

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