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Q&A #17351

Teachers' Lounge Discussion: alternative ways to mulitply

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From: Sharon Ohlhauser <sharohlh@charter.net>
To: Teacher2Teacher Public Discussion
Date: 2010111121:26:43
Subject: Re: bow tie multiplication

On 2007112422:30:43, julius nadas wrote:
>I believe that the bow-tie method was used back in Abraham Lincoln's
>day and is just a graphic way of showing the FOIL method for
>multiplying any pair of two digit numbers.  I hope this comes out OK
>in your browser:
>
>take 23 times 45.
>In foil you add these terms:
>20x40 + 20x5 + 3x40 + 3x5
>
>in bow-tie you draw this picture:
>
>
>20  +  3
> |\   /|      
> | \ / |     
> |  X  |     
> | / \ |      
> |/   \|
>40  +  5
>
>(see the bow tie) 
>and you multiply the numbers that are connected by lines.
>
>
>



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