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Welcome to my math blog! The purpose of this blog is to help you stay informed about our learning and experiences that have taken place during our math class. I have also included links your child (and you) may want to use in order to supplement math learning in 5th grade.

Tuesday, October 1, 2013

Estimating with Adding and Subtracting Decimal Numbers

We definitely put our thinking caps on today!  The kids have spent years learning the rounding rules.  They know how to round, but not really WHY we round.  I explained that most of us use rounding/estimating daily.  

  • I estimate the amount of money I am about to spend at the grocery store before I check out.  
  • I estimate how much farther I can get on my remaining gas before I need to fill up.
  • I estimate time constantly:  About how much more time do I give before we pack up to switch classes.  About how much longer to lunch!  :-)
  • I estimate the number of candies in the jar so that I can win the jar and eat the candy!

So today, we worked with adding and subtracting decimals again.  I wanted them to work with adding decimal points to whole numbers, and lining up the decimal points and creating equivalent decimal numbers BEFORE adding and subtracting.  However, I threw them a loop... we had to estimate our answers first!

I explained that estimating an answer before solving the problem allows us to see if our solution is reasonable.  Is our solution close to our estimation?  If so, we are probably correct!

If you would like to view the lesson, please follow the link: http://www.youtube.com/watch?v=4VySp0oXmdo

Homework:  edmodo.com

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