Why can't mathematicians add just like they multiply fractions? The resource provides a counterexample to show that the same rules for multiplying fractions do not work for addition. Using the counterexample, learners see the proper way to add fractions with common denominators. 

Concepts

adding fractions, adding fractions with common denominators, subtracting fractions, subtracting fractions with like denominators, fractions, fractions common denominators, addition, subtraction

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Additional Tags

math

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Instructional Ideas

• To start, use fraction models to demonstrate the addition of fractions

Classroom Considerations

• Pupils should understand fractions as division problems
• Assumes the class knows how to simplify fractions

• This video is hosted on YouTube

Pros

• Uses a fraction model to demonstrate why the improper way of addition does not work
• Includes mathematical terms to describe like fractions

Cons

• None

Common Core

SL.4.2 4.NF.B.3.a 4.NF.B.3.c MP6