Fact FamiliesDate: 09/21/2000 at 14:17:20 From: Ann Treacy Subject: Fact Families What is a "fact family?" Date: 09/21/2000 at 17:50:58 From: Doctor Rick Subject: Re: Fact Families Hi, Ann. A fact family can be FOUR -- FOUR -- FOUR facts in one! When you memorize an addition fact like 2 + 3 = 5, three other facts come along for free. The set (fact family) is 2 + 3 = 5 3 + 2 = 5 5 - 2 = 3 5 - 3 = 2 Some fact families have only two members. For instance, 2 + 2 = 4 4 - 2 = 2 Multiplication and division facts come in families in just the same way. For instance, 3 * 5 = 15 5 * 3 = 15 15 / 3 = 5 15 / 5 = 3 These are things we knew, but they didn't teach the term in school when I was a kid. It's a good term, though, I think. - Doctor Rick, The Math Forum http://mathforum.org/dr.math/ |
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