



 
Hi Camasha, The first fact family your daughter saw was probably made up of something like 2, 3 and 5, that is two positive numbers and their sum. There are then four members in the family.
If you apply the same rules to 9, 9 and 18 you get
Facts 2 and 4 are redundant so the fact family only has two members
This shouldn't be surprising. There are many kinds of families, average families (a man a woman and two and a half children), extended families, single parent families, blended families, ... Penny
 


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