Sunday, March 6, 2011

Learning Fact Families

One of the great ways to learn addition and subtraction facts or multiplication and division facts is to memorize not the facts but the "fact families." For example, in addition/subtraction the numbers 3, 5, and 8 form a fact family with the following facts: 3+5=8, 5+3=8, 8-3=5, and 8-5=3. In multiplication/division an example family for the numbers 4, 5, and 20 would be: 4x5=20, 5x4=20, 20/5=4, 20/4=5. Fact families are great because by memorizing that three numbers have a relationship to each other, you actually memorize four facts. Many of us have done this informally and will almost expect to see the third number of a fact family when faced with the other two numbers.

There are commercial three sided flash cards available from Trend. But for a lower cost alternative, here is a great page from Math Cats with fact family cards you can print yourself, a nifty holder for them which covers up part of the card, and many games for both addition/subtraction and multiplication/division.

Try fact families especially with kids who are good at seeing relationships between information and for those who haven't been successful with regular flash cards. 

Article by Heddi Craft

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