## Reflection: Modeling Towering Fractions - Section 3: Guided Practice

A bar diagram is a more "mature version" of the part- part-whole model used to teach students addition and subtraction.

In the case of this lesson, the bar diagrams students are creating to organize their thinking is in fact a part part whole model.  Students are using fractions, rather than whole numbers.

The reason we call these diagrams bar diagrams and not part-part-whole models is because at this level, the name can become limiting.  If a problem requires addition of more than one addend, if repeated addition is used (multiplication), or if a problem is about division.  All of these operations can be represented by extending the part-part-whole model.  This progression is taught to the students as they learn the new concepts.

Bar Diagram
Modeling: Bar Diagram

# Towering Fractions

Unit 2: Adding and Subtracting Fractions
Lesson 9 of 11

## Big Idea: Today students work to showcase their knowledge of working with fractions with unlike denominators.

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Standards:
Subject(s):
Math, Fractions, problem solving, Critical Area, Literacy in Math
75 minutes