# Pencil Measurements

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## Objective

SWBAT make a line plot to display a data set of measurements in fractions of a unit (1/2, 1/4, 1/8) and solve problems involving addition and subtraction of fractions by using information presented in line plots.

#### Big Idea

Students will measure various pencils to the nearest 1/4 inch, make a line plot, and solve problems involving addition and subtraction of fractions.

## Student Practice

100 minutes

Continued Practice

Today's lesson was a continuation of yesterday's lesson, Measuring and Comparing Lengths of Objects. Some students needed more time to complete yesterday's activities! Once they were finished, they moved on to this pencil measuring task.

Choosing Partners

Picking math partners is always easy as I already have students placed in desk groups based upon behavior, abilities, and communication skills. Before students began working, I asked them to discuss how they would like to support each other today. I gave them many examples: Do you want to take turns talking out loud? Do you want to solve quietly and then check with each other? Or do you want to turn and talk anytime you get stuck? Students always love being able to develop a "game plan" with their partners!

Powerpoint Presentation

To help teach today's lesson and provide students with guided practice, I created a Google Presentation: Measuring Pencils. Students copied the presentation, making the document their own. This way, they could make changes to their own document instead of the teacher template.

On Slide 1, we reviewed today's goal and students inserted their own names By: "Student Name."

Minimal Modeling

I provided minimal modeling for the lesson today as students were already familiar with measuring objects, recording data, making line plots, and solving problems from yesterday's lesson.

I simply pointed out the location of the pencils and briefly went over the presentation slides.

Labeled Pencils

Prior to today's lesson, I collected 18 pencils of different lengths. I labeled each pencil with a letter in the alphabet (A-R) using masking tape and a black marker. Next, I placed the pencils on the counter for students to measure: Labeled Pencils.

Measuring & Recording Pencil Lengths

Again, as students completed their work from yesterday, they began today's task, measuring pencils. I was amazed at how excited students were to measure pencils! At one point I had to remind them that it was not a competition!

As students measured each pencil to the nearest 1/4 in with their partners, they recorded the measurement on Slide2 and Slide3 of their presentation.

When finished, I asked students to check their measurements with other students. Great conversations resulted and this definitely encouraged students to engage in Math Practice 3: Construct Viable Arguments!

Here's an example of a student measuring and recording a pencil length: Pencil H.

Monitoring Student Understanding

During this time, I conferenced with every group. My goal was to support students by providing them with the opportunity to explain their thinking and by asking guiding questions. I also wanted to encourage students to construct viable arguments by using evidence to support their thinking (Math Practice 3).

1. What did you do first?
2. What do you need to always remember?
3. Does that feel right?
4. What do you need to remember when measuring to the nearest 1/4 inch?
5. What makes more sense to you?
6. Does that always work?
8. At what mark do you always line the pencil up with?

Line Plot and Problem Solving

Just as we had done yesterday, students constructed a line plot (on Slide4) to represent all the pencil measurements. Some students struggled with a title. I reminded them that titles should have a who and a what. Other students struggled with an x-axis label. I provided support whenever necessary by asking guiding questions: Copying & Pasting Xs and Constructing Line Plots.

I also loved encouraging students to think deeply about their line plots: Analyzing the Line Plot

Finally, students moved on to problem solving on Slide5Slide6, and Slide7

Here, Student Solving 6 3:4 - 3 3:4, a student explained her thinking after showing her work on their white board and capturing a photo of her work.

Here's another student, Student Solving 7 1:2 - 3 3:4, who did a great job taking jumps to the left on the number line to demonstrate subtraction.

Other students chose to add up to subtract: Adding Up to Subtract.

Again, as students finished, I asked them to share their work with others to make sure other students agreed with their thinking.