Day 26 – Greatest Common Factor

The groups each got to present their work from yesterday’s Candy Challenge.  It was great to hear them once again talking about this “Greatest Common Factor” without actually knowing that’s what they were searching for.  A few groups gave their classmates a preview (unbeknownst to them) of what I would be showing them in the lesson today on GCF.  One group showed us how they used prime factorization to find the greatest common factor of 90 (tootsie rolls) and 120 (smarties).  Another group carefully listed all of the factors of both 90 and 120.  They connected them with a “rainbow” and explained that once you have all the factors listed, you can just find the biggest one that is in common.  And with that, they just taught my lesson!  Image

Still, we went through the two methods: prime factorization and making a list of all factors.  We only had a few minutes to practice before the bell rang and it was time to go…


About Gretchen Simmerson

Middle School math teacher living in Austin, Texas.
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