Building Fractions Using Units
Lesson 2 of 13
Objective: Students will be able to identify and represent unit fractions.
Ask the children to turn and explain fractions to their partner using what they are learning. Be listening for students to explain that in order to be considered a fraction, the "piece" must be equal to all the others in the whole.
The turn and talk prepares students to articulate their thinking, and so I ask several students to share their thinking to the class using their own language.
Next, I show the students a strip of paper and tell them that we will consider this as our ONE WHOLE. This is such a huge concept for the students to understand. Don't skip talking about what a whole means. Using a context may help some students reason through this language. Food really is relevant to pretty much everybody - the only problem is that the pieces won't be precise units. But when it comes to dividing up "yummy" food, students understand the importance of "fair" or equal shares. And all fractions have to be "fair" or equal sized shares.
Now comes the fun! Give the students six strips of construction paper of different colors and ask them to choose one to be their WHOLE. Write the number 1 on the strip, as well as the word whole. Explain that you are creating a fraction strip poster. Glue the whole down at the top of the file folder. (I am using a file folder because I am having the students create a fraction resource kit. The outside of the folder will have number lines and other necessary references.)
Next, students fold a strip in half. Using fractional words, I support students in explaining that they just created a fraction. Work with them to name it using the vocabulary of a numerator and denominator. Don't forget to write the words "half".
Glue this down on the poster under the whole. Be sure to focus the students on lining the strips up so they are even. Some students might need a line on the left hand side to guide them in lining their pieces up evenly.
Repeat this demonstration by folding and naming the fourths with numbers and words with another strip.
Explain to the students that they will now move to their work spaces and fold and name eighths, thirds, and sixths on their own.
As the students work to fold and name sections of their strips, move around and confer with them. Watch for misconceptions and inaccurate folds.
This student is working to create fourths with his strip and figuring out why folding halves in half makes fourths.
A response comes from across the room from a student that is also trying to find the words to makes sense of fourths from halves.
After the students fold and name their fraction strips, they arrange them with the whole on the top, halves, fourths, eighths, thirds, and sixths.
How can we use halves to help make fourths?
What is the relationship between halves, fourths, and eighths? Do you see a pattern?
Do you see a pattern in the thirds and sixths?
If we used 3 of the eighths, what would be the name? (This question is an extension of the objective and orients the students to their work in the coming days.)
Continue with questions that probe student understanding of the fractional units represented in the fraction strips. This portion of the lesson is the springboard for understanding, modeling, and eventually visualizing unit fractions, and larger fractions made from those units. This is critical. It is also a perfect time to make sure all of the students have correctly named their strips.
At the end of the lesson, students share their posters with each other. This is intended to be an interactive experience, not just a report out, so I have the students compare the work with one another and revise as needed.
Then, I rephrase the objective of the lesson to prepare them for tomorrow's lesson, where they will become the teachers and create a training video for others.
As a home practice piece and in order to prepare for the next lesson, give the students the following blank fraction strip poster.
Have them label each unit piece with the corresponding number and words.
Then, ask them to write out their ideas for their training video the next day. Explain to them that their video will teach other students how to create their own fraction strip poster and how and why each piece has the name it does.