Tuesday, December 18, 2012

Composing and Decomposing Fractions

CCSSM 4.NF.3b reads as follows:
Decompose a fraction into a sum of fractions with the same denominator in more than one way, recording each decomposition by an equation.  Justify decompositions, e.g., by using a visual fraction model.  Examples: 3/8 = 1/8 + 1/8 + 1/8; 3/8 = 1/8 + 2/8; 2 1/8 = 1 + 1 + 1/8 = 8/8 + 8/8 + 1/8.
Here's a little fraction activity that can move your kiddos in the right direction toward that understanding.  Be sure to provide manipulative support (concrete) and have students record their work with a model (representational).  A suggestion for how to draw the model is shown below.  Click here to grab your freebie!  As always, I love to hear how you use this in the classroom.  :)


  1. Thanks for this! I will be starting my CCSS unit on fractions after Christmas...and just reading the standards makes my head hurt! I like the way you explained this one.

    1. Ha ha! I totally understand. Glad this helps. :)

  2. Thanks so much! I know this will be a help to my students; I look forward to using it!


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