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Where We’ve Been……. Properties, Part I…….. If I say “order,” you say……… If I say “grouping,” you say……… If I say “identity,” you say……… If I keep saying “properties,” you are probably thinking ……. commutative associative Value stays the same

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### Transcript of Where We’ve Been……. Properties, Part I…….. If I say “order,” you say……… If I say...

• Slide 1
• Slide 2
• Where Weve Been. Properties, Part I.. If I say order, you say If I say grouping, you say If I say identity, you say If I keep saying properties, you are probably thinking . commutative associative Value stays the same
• Slide 3
• Where We Are Going. Today, we are going to investigate one of the most important properties you will use this year and in future classes. Distributive Property Algebra Just listen. Associative PropertiesCommutative Properties Identity Properties Order of Operations Translating Expressions
• Slide 4
• The Distributive Property 2.4 p. 40 The Big Dog of Properties !!!
• Slide 5
• Naming What You Know Once again, you already use this property. Lets say you bought 23 CDs for \$6.00 each. \$6 each Is there a way you could mentally rearrange these values to find your total without a pencil and paper? Notes.
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• Many of you would mentally multiply the \$6 by 20, multiply the \$6 by 3, and add the products. 6(20 + 3) \$6 each Lets try this mentally. 6(20) 120 + 6(3) 18 = 138 If you have ever tried this mental math, you have used the distributive property!!
• Slide 7
• What Is Our Objective? Use the distributive property to rewrite and simplify multiplication problems What property will we use? What will we do with this property? Distributive Property We will simplify multiplication problems with this property! Notes.
• Slide 8
• To Your Notes Vocabulary: This is given in your notes The Distributive Property states that multiplying a sum (or difference) by a number gives the same result as multiplying each number in the sum (or difference) by the number and adding (or subtracting) the products. Now lets use real words to understand the official definition. Just listen.
• Slide 9
• What does this mean? Lets take a basic multiplication problem: 6 x 23 We will rewrite 23 as an addition problem. 6 x (20 + 3) Now we will multiply the 6 by EACH of the values that add up to 23. 6 x 20 + 6 x 3 120 + 18 138
• Slide 10
• What it looks like. Algebraically, the distributive property is defined with variables. a(b + c) = a(b) + a(c) or a(b - c) = a(b) a(c) Think about our CD example. In expanded form, how would we write 23? 20 + 3 Now, lets use our price of 6 6(20 + 3) = 6(20) + 6(3) = 120 + 18 = 138 Notes.
• Slide 11
• Guided Practice: 5 x 27 Lets take the larger factor and write it in expanded form. 5 (20 + 7) Remember, no sign means to multiply! Lets distribute the 5. It is the factor used on both the 20 and the 7. (5 x 20)+(5 x 7) = (100) + (35) = 135
• Slide 12
• 4 x 28 Take the larger factor and write it in expanded form. 4 (20 + 8) Lets distribute the 4. It is the value used on both the 20 and the 8. (4 x 20)+(4 x 8) = (80) + (32) =112 7 x 108 =7 (100 + 8 ) (7 x 100) + (7 x 8) =700 + 56 = 756
• Slide 13
• What Is Our Objective? Use the distributive property to rewrite and simplify multiplication problems What property will we use? What will we do with this property? Distributive Property We will simplify multiplication problems with this property!
• Slide 14
• Small Group Work With your partners, use the pattern we started in your notes to simplify these examples using the distributive property. First rewrite the problem, breaking up the larger value. Next, show how the single multiplier is distributed to both parts of the expanded number. WE ARE ONLY BREAKING UP THE LARGER VALUE AND DISTRIBUTING THE SINGLE-MULTIPLIER! After completing the first four problems, move on to the next three. Try to find a value (evaluate) the expression after you rewrite it! I will check as you work to make sure you are progressing accurately. You will have about 10 minutes.
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• 1) 8(43) = 2) 5(67) = 3) 9(42) = 4) 3(53 ) = 403 9 9 50 3 Give me a sign when you finish this section. 8( 40 + 3) 5( 60 + 7) 8( ) + 8 ( ) 5( ) + 5 ( )60 7 9( 40 + 2) ___(40) + __ (2) 3( 50 + 3) 3( ) + 3 ( ) 344 335 378 159
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• 5) 7(52) = 7( ) 6) 9(107) = ___ ( ) 50 + 2 7(50) + 7(2) 350 + 14 =364 9 100 + 7 9 (100) + 9(7)= 900 + 63 = 963
• Slide 17
• Application FoodCost Organic Chili\$6.00 Chicken Tacos\$4.00 Fruit Salad\$5.00 Organic Salad\$5.00 Veggie Plate\$6.00 Big Group Menu Discuss with your group.. The 6 th graders ordered from the Big Group Menu. They ordered 22 organic chilis and 8 veggie plates. Create a problem using the distributive property to represent this situation.
• Slide 18
• Take a moment to reread your definition of the distributive property. Did we leave something out?????? We rewrote all problems as addition. Lets look at two problems and change them to subtraction.
• Slide 19
• Our first problem in the Guided Practice was 5 x 27 Could we use a subtraction problem to create a value of 27???? 30 3 = 27 5 x 27 = 5 ( )30 - 3 5(30)- 5(3) 150 - 15 = 135
• Slide 20
• Could we use a subtraction problem to create a value of 8(78)???? 80 2 = 78 8 x 78 = 8 ( )80 - 2 8(80)- 8(2) 640 - 16 = 624
• Slide 21
• Think Critically Look at the expressions represented by the properties we have studied.. 14x 3 = 3 x 14 14 + 4 = 3 + 14 (4 x 5) x 12 = 4 x (5 x 12) (4 + 5) + 12 = 4 + (5 + 12) 12 X 6 = (6 x 10) + (6 x 2) What is the one distinct difference that separates the distributive property from the commutative and associative properties?
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• Lets Summarize What was the goal of our lesson? Have we accomplished our lessons objective?
• Slide 23
• Distributive Property Extension You can apply the Distributive Property to unknown values (models). = 1 = x You are looking at a model that represents 2x + 5 that is written three times. Instead of writing 2x + 5 + 2x + 5 + 2x + 5, we could write 3(2x + 5) We have to use the distributive property to pull the values out of the parentheses 3(2x) + 3(5) We use the associative property to multiply 3(2)x = 6x and we multiply 3(5). 6x + 15 represents our simplified value. We can do no more.
• Slide 24
• ( + ) 3 2x 5 6x + 15 Use your imagination! What just happened here? (3 2x) + ( 3 5 ) = 6x + 15
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• What is our common factor? Which number is used twice in multiplication? What do we have left?
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• You can apply the Distributive Property to unknown values (models). = 1 = x What expression represents this model? We have 3x + 7 that is written two times. 2(3x + 7) = 2(3)x 6x + 2(7) + 14
• Slide 28
• Lets add one more value to this process..
• Slide 29
• What have we done? We have used the distributive property to solve multiplication problems. We have written problems with variables using the distributive property.