Saturday, October 12, 2013

Expanded Algorithm

         My class and I have been working through 2-digit by 2-digit multiplication this week.  We have discovered several strategies.  The students learned how to decompose factors last year when we learned about the Distributive Property of Multiplication. 

  15 x 18 
(10 x 18) + (5 x 18)
  180    +     80
  260

        We have also learned about Open Arrays,


which we call the Box Strategy because, let's face it that much better describes the strategy.  Of course the ultimate goal is to get to the Standard Algorithm . . . that is not quite in the cards for everyone, yet.

        We did however, stumble upon the perfect compromise, enter the Expanded Algorithm . . .

 

        Since I NEVER remember to take any pictures I perused Pinterest and of course my web-based research did not let me down.  I have linked the pictures I snagged to try and give credit to the creator. 

        Just wanted to share in case you were searching for a strategy to use with your kiddos who just aren't quite ready/can't get a handle on the Standard Algorithm.  Happy times tabling!!!

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