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Using the Distributive Property


Date: 08/23/2001 at 20:17:06
From: Jennifer Cmajdalka
Subject: Distributive property 

My math teacher told us to work problems like this:

            a(b-c)= ab-ac

If we do them like that, then how do I do these problems?

                67(40)
                 AND
                210(800)

I hope you can help me! She said not to do multiplication on that, but 
to work it the way you work a distributive propery. HELP! Thanks!

Jen


Date: 08/24/2001 at 16:33:52
From: Doctor Ian
Subject: Re: Distributive property 

Hi Jen,

I think what she wants you to do is to break one of the terms up into 
a sum, e.g., 

  (49)70 = (40 + 9)70 

         = (40)70 + (9)70

         = 2800 + 630

         = 3430

Actually, this is a good trick to use to do multiplication in your 
head, so it's worth spending a little time practicing it. 
  
But mostly, I think she wants you to get used to looking for 
opportunities to apply the distributive property, since once you get 
to algebra, it's going to be one of your best friends!

Does this help? 
                 
- Doctor Ian, The Math Forum
  http://mathforum.org/dr.math/   


Date: 08/24/2001 at 20:17:06
From: Jenny L Cmajdalka
Subject: Re: Distributive property

Thank you for helping me! That is what she wanted! 

Jen
    
Associated Topics:
Elementary Addition
Elementary Multiplication

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