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Math For Life Situations Vicki Angel Manuel A. Navarro

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1. Understand Ratios 2. Offer instructors an effective, easy, relevant way to teach percents using the proportion method

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WHAT IS A RATIO? COMPARISON BETWEEN TWO QUANTITIES OR NUMBERS. 4 puzzle parts to 3 gears WHAT IS THE RELATIONSHIP BETWEEN THEM? For every 4 puzzle parts, there are 3 gears.

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RATIOS CAN BE WRITTEN IN 3 DIFFERENT WAYS: · 4 to 3 · 4 : 3 · 4 / 3

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More about ratios Ratios can be reduced by division. Example: 6 / 4 = 3 / 2 when divided by 2 / 2 Ratios can be increased by multiplication. Example: 6 / 4 = 18 / 12 when multiplied by 3 / 3 Order is important. Example: 4 full time to 5 part time workers it is not the same as 5 part time to 4 full time workers

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What is a proportion? In a proportion there are 2 ratios combined by the equal sign ( = ). This makes both ratios equivalent

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For example: 30 to 6 = 5 to 1 How do we know? By cross multiplication 30 X 1 = 6 X 5 30 = 30

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How do you introduce Percents? 1. What is 20% of 40? 2. 45 is 45% of what number? 3. 35 is what percent of 70? 4. Students get confused on how to solve these problems!

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1. When do I multiply? 2. When do I divide? 3. How do you multiply or divide with percents? 4. Please, give me an easy way to do it! 5. The answer is a PROPORTION!

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All percent problems are composed of three parts ◦ Percent ◦ Part ◦ Whole The answer lies in identifying which one is missing.

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is of % 100

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Start with teaching students how to identify the three components using CLUE WORDS ◦ Is – defines the part, or portion ◦ Of – defines the whole or original amount ◦ % symbol – defines percent

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8 is 20% of 40 Clue Words ◦ IS = Part, portion. ◦ % = Percent Symbol ◦ OF = Whole, original.

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8 is of % 100 is 20% of40 100 IS OF %

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2 & 3 Pages Do

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What is 20% of 40? 40 ? 20% 100 Cross Multiply 100 8 20 X =800 Divide by the other number =8 800 ÷

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8 8 is 20% of what number? ? 20% 100 Cross Multiply 40 X =800 ÷= 8 100 Divide by 3 rd. Number 20 40

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8 8 is what % of 40? 40 ? % 100 Cross Multiply 20 X =800 ÷= 8 100 40 Divide by 3 rd. Number 20 %

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4 - 6 Pages Do

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1. Multiplication? Division? 2. Eliminates the need to convert percent into decimals. 3. Introduces students to variables. 4. Fractions, Unit conversions and Geometry applications.

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1. Q & A. Are there any questions? 2. Do you have any suggestions? 3. Do you think this is something you can use? THANK YOU!

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