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Published byIris Howard Modified over 9 years ago
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Opening Activity Choose a strategy to solve the problem below. Charles, TJ, Taylor, and Judy biked in a 10-mile charity race. TJ was last in 39 minutes 6.5 seconds. Taylor finished 2 minutes 0.3 seconds ahead of TJ. Judy finished 47.8 seconds ahead of Taylor. Charles finished 1 minute 57.4 seconds ahead of Judy. What was Charles’ time? STRATEGIES Draw a diagram Make a graph Make an organized list Try, check, and revise Work backward
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Multiplying Decimals Lesson 1-7
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To Multiply: 1. DO NOT line up the factors by the decimal. 2.Place the number with more digits on top. 3.Line up the other number underneath, at the right. 4.Multiply 5.Count the number of decimal places in each factor. 6.Use the total number of decimal places in your two factors to move the decimal in your product to the LEFT.
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Example: 5.63 x 3.7 5. 63 3.73.7 x 1 2 4 4 39 098 1 16+ 13 1 8 1 0 1 2 Two decimal places Move three places to the left. One decimal place Three decimal places total
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Example: 0.53 x 2.618 (place factor with the most digits on top) 2.618 has more digits (4) than 0.53 (3), so it goes on top. 2. 618 0. 53x 4 2 58 1 7 00 4 90 3 13 000000+ 457 1 831 Decimal Places three two Five total.
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Try This: 6.5 x 15.3 15.3 6.5x 5 1 6 2 7 08 1 1 3 9+ 54 1 99 one two.
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Multiplication Properties Commutative Property of Multiplication: Factors can be multiplied in any order. Example: 12 x 5 = 5 x 12 Associative Property of Multiplication: Factors can be grouped in any way. Example: (2 x 3) x 5 = 2 x (3 x 5) Identity Property of Multiplication: The product of any number and one is that number. Example: 18 x 1 = 18
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Classwork:. Play Hoop Shoot and Football Math to help you multiply decimals Complete Multiplying Decimals worksheetHoop Shoot Football Math The above image is Michigan’s Franklin Cider Mill provided by http://www.michigan.org/Things-to-Do/Attractions/Farms-and-Mills/Default.aspx http://www.michigan.org/Things-to-Do/Attractions/Farms-and-Mills/Default.aspx HOMEwork: pg. 37-38, #2-54 evens
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