Thursday, August 22, 2013

Prime Factorization Success!

Runde's roomFollowing the frustration this week was a deeply satisfying "ahhhhhhhh" moment on Tuesday. My students were learning about prime factorization. I pulled together a few pieces from several great lessons. One idea came from an ace teacher, Jen Runde!  http://www.rundesroom.com/

I started the lesson by holding up a bag marked with 300 on the outside. I asked the students to do an "I Notice, I Wonder" journal entry to spark some interest. After some sharing, I revealed the colored shapes/numbers in the bag.  More "I Notice, I Wonder" writing and sharing. I was hoping students would notice there were only prime numbers and the fact that you could use those numbers to get the product of 300.  Paydirt!  At least one student in each class came up with the primary ideas. Never say for the students something they can say!

I had more bags with other numbers: 18, 30, 48, 56, and 75. I had the students work with partners to figure out the prime numbers in each bag I held up. They recorded their ideas in their interactive notebooks. We also talked about how we could find all the other factors of each number by combining the prime factors. This part of the lesson came from an article, "Moving Beyond Factor Trees," by Terri L. Kurz and Jorge Garcia in Mathematics Teaching in the Middle School. This was a powerful lesson for students. Rather than starting with factor trees and teaching a procedure, the students were able to discover through their intuition and understanding of prime numbers, how to do the prime factorization! Today we'll add the exponential form to the factorization.

Thanks to my online colleagues for the great ideas!

 




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