Double digit multiplication

Discussion in 'Fourth Grade' started by nboris827, Oct 13, 2010.

  1. nboris827

    nboris827 Rookie

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    Oct 13, 2010

    Hi all,

    Next week I am teaching double digit by double digit multiplication (ex. 25 x 14). I know this can be a very dry topic, so does anyone have anything fun to jazz it up? Hands-on ideas would be great!

    Thanks!
     
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  3. teacherfourth

    teacherfourth Rookie

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    Oct 13, 2010

    OHH I hope someone has something... I agree it can be dry.
     
  4. Aliceacc

    Aliceacc Multitudinous

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    Oct 14, 2010

    No real ideas.

    But please allow me to get up on my soapbox with a brief commercial against the lattice method. It doesn't teach the kids the skills they'll need when they need to multiply polynomials down the road. It doesn't increase their understanding of place value. All it does is give them the correct answer. If that's the objective, hand them a calculator.

    OK, rant over.
     
  5. worrywart

    worrywart Companion

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    Oct 14, 2010

    I think a good place to start is similar to how you would do an area model...partial products?? Anyway you would have 20 and 5 across the top, and 10 and 4 down the side. Then underneath you would have a 2 x 2 box and they would multiply the

    20 x 10 (put 200 in upper left box)
    20 x 4 (put 80 in lower left box)
    5 x 10 (50 in upper right box)
    5 x 4 (20 in lower right box)

    add 200 + 80 + 50 + 20 = 350

    I think that this is a good lead in to standard multiplication so that they will understand the place values they are multiplying. Of course, after they learn what it all means, I would have them use the standard way if possible!

    No lattice!
     
  6. TeachinHicks

    TeachinHicks Comrade

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    Oct 15, 2010

    I just got through the same rant with my other teacher in 4th that is the Math. She's trying to teach them lattice for 2 digits times 1 digit. They are completely lost...my daughter being one of them. I told my daughter just do it the traditional way!!! I will not be teaching lattice to my students and am trying to get her not to either!
     
  7. corney

    corney Companion

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    Oct 15, 2010

    May I ask what is lattice in regards to Muliplication?
     
  8. Missy

    Missy Aficionado

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    Oct 16, 2010

    Corney - sorry I don't know how to show lattice on the computer, but google it and it will turn up - I find it very confusing.

    I start with base ten blocks and we lay it out so they see what is happening.

    After a day or so I let the kids make up the problems and that seems to keep their interest. I usually hit it really hard for 3 -4 days, and then do about two problems a day for the next few weeks. It seems like some kids just need some time for it to soak in, so we take it slowly.
     

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