Fourth graders have been working on addition and subtraction of fractions with like and unlike denominators. We have used multiple representations and a variety of manipulatives including fraction strips and circle models. After students developed good understanding of adding and subtracting fractions with manipulatives, we moved into using the algorithm by finding least common denominators. Although students were introduced to the “butterfly method” for finding equivalent fractions, they were warned to use the method judiciously as it often results in very large denominators. Very large denominators mean lots of work when simplifying. Sometimes a more obvious common denominator is easier to use for addition and subtraction and results in fewer calculation errors.
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Mrs. GregoryMrs. Gregory has been a teacher for 25 years. She lives in Montpelier with her husband, two daughters, and two dogs. Archives
December 2016
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