Reflection: Connection to Prior Knowledge Decomposing & Composing Fractions - Section 2: Teacher Demonstration


Although fractions don't follow all the same rules as whole numbers, such as the larger the digit, the larger the quantity, there are many connections that can still be made. For example, fractions on a number line are ordered from least to greatest, just like whole numbers. 

During this lesson, I was proud of myself for spontaneously using prior knowledge to help students understand how to decompose fractions. 

I drew the following model on the board, Decomposing 20 is similar to decomposing 1:2, and explained: If I have the number 20, I can decompose the 20 into parts that add up to 20. For example... 10 + 10. Just like you can decompose whole numbers, you can decompose fractions: 1/2 can be decomposed into 1/4 + 1/4. I then related this to the area model on that slide of the presentation. 

Connecting fractions to my students' whole number understanding seemed to help them make more sense of parts of a whole. 

  Connection to Prior Knowledge: Whole Number Connections
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Decomposing & Composing Fractions

Unit 10: Fractions
Lesson 7 of 16

Objective: SWBAT prove two fractions are equivalent by decomposing & composing fractions.

Big Idea: Students will add and take away lines in area models to prove two fractions are equivalent.

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3 teachers like this lesson
Math, Fractions, Measurement and Methods, area model, decomposing, composing, ruler, fraction equivalency, fraction tiles
  130 minutes
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