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    Fact families | 
  2009-08-24 | 
   
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  From Camasha: I am trying to help my daughter with fact families.  I understand the premise from your previous explanation on the site .  Generally when applying addition and subtraction their are two add and two subtraction utilizing all three numbers.  However what do you do when you have a series like like 9, 9, 18 Answered by Penny Nom. | 
   
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