new common core standards for multiplication - ProTeacher Community





lovetheu.p. lovetheu.p. is offline
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lovetheu.p.
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new common core standards for multiplication
Old 01-28-2012, 10:07 AM
 
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I am trying to adapt my multiplication lessons for my third graders this year to match the common core. Commutative and associative properties go well but I am looking for some good concrete ways to teach the distributive property to them.

Anybody have ideas that have worked for them?

Here is the standard for third grade
Understand properties of multiplication and the relationship between multiplication and division.
5. Apply properties of operations as strategies to multiply and divide.2 Examples: If 6 4 = 24 is known, then 4 6 = 24 is also known. (Commutative property of multiplication.) 3 5 2 can be found by 3 5 = 15, then 15 2 = 30, or by 5 2 = 10, then 3 10 = 30. (Associative property of multiplication.) Knowing that 8 5 = 40 and 8 2 = 16, one can find 8 7 as 8 (5 + 2) = (8 5) + (8 2) = 40 + 16 = 56. (Distributive property.) (Associative Property 2 , Commutative Property 2 , Basic Distributive Property )


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ashleigh_60 ashleigh_60 is offline
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distributive property
Old 01-28-2012, 01:54 PM
 
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I've used arrays and base ten blocks to teach the distributive property. Personally, I felt like the base ten blocks confused my students, so I don't use them anymore. However, that could have been my fault, because that was one of the first times I had taught the distributive property, and I was a little unsure of it myself. I do like using arrays (with grid paper) to get students to find the partial product of each digit in the problem. (I could explain this much better with pictures

I used to hate teaching it, but my students usually like it-go figure.
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iteachrfuture iteachrfuture is offline
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Snip, Snip
Old 01-28-2012, 03:00 PM
 
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Hello! I recently tested teaching this on my third graders. They enjoyed it.

Ex. 9 x 7

I tell the children that they can use the distributive property when they are multiplying and they don't know how to count by one of the factors. It's hard to explain, but I will do my best.

materials: strips of paper, scissors, crayons, markers or other writing devices, worksheet.

1. Have them write the problem (large) on a strip of paper.
2. Have them cut the factor off that they don't know.
3. Have them flip the cut unknown factor over and come up with 2 numbers they do know the facts for that will add up to the factor. (2 + 5)
4. Cut the factor in half and write each of the new factors on the blank backs.
5. Place one of the numbers back into the original problem and multiply. That answer goes on the worksheet in the first part of the addition problem. 18 + ___ =
6. Switch it out for the other number and multiply again. Place answer in second part of addition problem. 18 + 45
7. Add. 18 + 45 = 63

Depending on how well they understand and practice the concept, you may have to set where they put the numbers differently.
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ashleigh_60 ashleigh_60 is offline
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Old 01-29-2012, 05:22 PM
 
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I didn't read the standard careful before I posted (shame on me-I can't fuss at my students tomorrow), and I have to say that is REALLY confusing. I currently have to teach the distributive property with 2 and 3-digit numbers, which makes a lot of sense to me. I wonder is students will only use the distributive property with 1-digit numbers with the CCS, or if they will have to use it with larger numbers too. That will make a big difference in how and how long I teach it.
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