Fact Family vs. Number FamilyDate: 09/24/2001 at 20:42:02 From: Marilee Subject: "Fact Family" vs. "Number Family" I am trying to help my sister answer my nephew's question. We have all gotten quite clear on what a fact family is, but what seems to be left assumed, is that we just automatically then know what a number family is. We can't come up with a clear, simple answer to this. Please help. Concerned Aunt and Parent Date: 09/25/2001 at 08:44:02 From: Doctor Rick Subject: Re: "Fact Family" vs. "Number Family" Hi, Marilee. I am not an elementary teacher, so I have not been trained to use these terms. I am a bit older than you, so I did not learn these terms in school, either. They are not terms used by mathematicians, but terms currently in vogue in the teaching of math. I have learned what "fact families" are through answering other students' and parents' questions. Fact families are explained in this item in our Dr. Math archives: Fact Families http://mathforum.org/dr.math/problems/atreacy.09.21.00.html A number family is an "extended family," while fact families are "nuclear families." A number family consists of all (addition) fact families that have the same largest number (sum). Thus, each column below is a fact family, and all the columns constitute the "6" number family: 6+0=6 5+1=6 4+2=6 3+3=6 0+6=6 1+5=6 2+4=6 6-6=0 6-5=1 6-4=2 6-3=3 6-0=6 6-1=5 6-2=4 I don't know how standard this terminology is. If what I have said doesn't fit with what you have seen, let me know and we'll try to figure out what your meaning is. Ideally all terms should be defined in a textbook when they are first used. This goes especially for pedagogical terms and others that parents cannot be expected to know. But I know that textbooks often are not ideal. - Doctor Rick, The Math Forum http://mathforum.org/dr.math/ |
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