Class Fractions

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Objective

Students will be able to create and identify benchmark fractions.

Big Idea

That fraction sure is a class act.

Opener

15 minutes

In this lesson students will be discussing the previous lesson’s investigation and building upon their knowledge of fractional models.  Students will be creating fractions using examples of student attributes and then going over ‘I can’ statements for the remainder of this unit. 

To begin this lesson students will have a small classroom competition using their fraction pieces sets. I pass out the sets of fraction pieces and instruct students to put all their pieces out in front of them facing down.  I have students mix up the pieces in front of them, being careful not to mix their pieces up their neighbors.  On the count of three I have students put all fractional pieces together with like pieces so that they have all pieces totaling one.  The trick is the students have to do this with the pieces facing down.  This way all the pieces are white and students have to rely on their eye sight of similar sized pieces.  I limit the competition to three minutes. 

Now that I have students once again excited about math, I move in to a whole group discussion based on the previous lesson’s investigation.  I use the discussion questions from the NCTM Illuminations website for the More Fun with Fraction Strips activity. 

What patterns did you notice when you compared fractions?

When you order the fraction pieces from largest (the "whole") to smallest (1/12s), what do you notice about the relationship between the size of the fraction and the denominator?

Do you think this relationship always holds true?

Does a similar relationship hold true for fractions where the denominator is some constant number?

Practice

30 minutes

The students will now practice creating fractions using attributes of their classroom.  This is based on Activity 12.3 of the second edition of Teaching Student-Centered Mathematics by John Van de Walle. 

I call up a group of five students and then ask students a question about the group.  Students remaining their seats will answer the questions by writing their responses on their whiteboard in numerical form and using a model.

Okay, looking at this group.  How many of them are wearing tennis shoes?  If you are up front and wearing tennis shoes, please raise your hand.  Everyone else, what fraction of the students are wearing tennis shoes? 

I call on a student to give their answer and explain their thinking by giving carefully formulated explanations to their peers(MP 6).  I go through another example with this set of five students then call upon a different group of students to come up and be the examples.  For the upcoming groups I choose a different denominator or number of students to be the whole. 

Closer

15 minutes

Now that we are a few lessons into this unit and I have brought to light some background knowledge of students, it is time to introduce the ‘I can’ statements for the remainder of the unit.  

I display the ‘I can’ statements for students and give them a brief preview of how we are going to cover statement in future lessons. 

I can explain the relationship between a part and whole.

I can create a model of a fraction.

I can create and identify equivalent fractions.

I can add and subtract fractions with like denominators.

I can add and subtract fractions with unlike denominators.

I can add and subtract mixed numbers.

I can solve real world problems involving fractions.