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Converting Fractions to Decimals. Adapted from free Powerpoints from the website: http://math.pppst.com/fractions.html. Discussion. Explain what a fraction is Explain what a decimal is Find a decimal that is equivalent to ¼ What method did you use to find this?. Problem of the Day.
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Converting Fractions to Decimals Adapted from free Powerpoints from the website: http://math.pppst.com/fractions.html
Discussion • Explain what a fraction is • Explain what a decimal is • Find a decimal that is equivalent to ¼ • What method did you use to find this?
Problem of the Day Complete the following Compare 5/13 to 4/9 Compare 0.384 to 0.4
Fraction is a comparison of two numbers • 5/13 to 4/9 • To compare the size of each part, the “whole” must be cut into the same size; the denominators must be the same
Converting Fractions to Decimals • To convert a Fraction to a Decimal manually, follow these steps: • Step 1: Find a number you can multiply by the bottom of the fraction to make it 10, or 100, or 1000, or any 1 followed by 0s. • Step 2: Multiply both top and bottom by that number. • Step 3. Then write down just the top number, putting the decimal place in the correct spot (one space from the right for every zero in the bottom number)
Method #1: Converting with Proportions • Example # 1: Express 3/4 as a Decimal • Step 1: We can multiply 4 by 25 to become 100 • Step 2: Multiply top and bottom by 25 3 = 75 4 100
Example # 1 continued…. • Step 3: Write down 75 with the decimal place 2 spaces from the right (because 100 has 2 zeros); • Answer = 0.75 • Can you explain what we just did? • Try to express ¼ as a decimal using method # 1.
Method #2: Convert by Dividing • Example #1: to write 5/8 as a decimal, we need to calculate 5 ÷ 8: 0.625 8 √ 5.000 So = 0.625 as a decimal. • Try this example: write 4/5 as a decimal using division (method #2).
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Lets Practice!! • We are going to use this website to fish out some fractions and decimals. • Lets see how well you understand this lesson. • Go to www.iknowthat.com • Select “Math” in the left margin • Select “Fishy Fractions” • Select “Fractions and Decimal Match”