Number Line Talk, Tasks, and Practice
NLT 3.1 A1
Measure Distance from Zero on Number Lines
NLT Objectives
This Number Line Talk targets the following essential concepts and strategies:
The value of a tick mark or point on a number line represents its distance from zero.
Measurement bars measure distance and label points on number lines.
Measuring a distance to the right of a known value on a number line can be represented by addition.
Measuring a distance to the left of a known value on a number line can be represented by subtraction.
Number Line Talk — Video
NLT Video 3.1 A1 — Measure Distance from Zero on Number Lines
NLMT — Video Challenges
Use the online interactive Number Line Measurement Tool to complete each Challenge in the Number Line Talk — Video.
NLT Video with Captions
Video Overview and Instructional Notes
The Video Overview and Instructional Notes outline the instructional highlights of this Number Line Talk and list the essential strategies and concepts that are introduced or reviewed. In addition, video pause points with instructional notes identify important representations, strategies, and concepts and offer suggestions for leading the group Challenge discussions with students.
VOIN for Number Line Talk 3.1 A1
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Materials List for Number Line Talk
Measurement Tool Options
The group Challenges in this Number Line Talk can be implemented using one of the following manipulative resources:
Foam Magnetic Measurement Bar Kit for a classroom whiteboard
Note: If this is the student's first introduction to measurement strategies on a number line, it is recommended that teachers use magnetic measurement bars (foam or printable) on a whiteboard to facilitate this NLT. This will provide students with a concrete experience with measurement strategies.Printable Magnetic Measurement Bar PDF for a classroom whiteboard
Click on this link to download and print this PDF for the Printable Magnetic Measurement Bars.Online interactive Number Line Measurement Tool
Click on this link to learn more about how to use the NLMT to facilitate a Number Line Talk.
NLT Materials List
The following number line segments and measurement bars are needed if you are using a classroom whiteboard to conduct the group Challenges in the NLT:
Conceptual Overview
Many students ignore the distance between tick marks and points on number lines when asked to label them with numbers. For example, the number lines below are incorrectly labeled. The incorrect strategies used to label these lines include extending patterns such as skip counting, counting by ones, and doubling. For each incorrect strategy, students ignored the distance between zero and 4 on the number line.
To address these students’ misconceptions, this Number Line Talk will demonstrate how measurement bars can be used to introduce the basic measurement strategy for number lines. Then, students can apply these measurement bar strategies to label and justify the correct values for tick marks and points on this line.
For a number line representing positive numbers (whole numbers, fractions, and decimals), the value of a point is its measured distance from zero. Applying this basic rule for number lines, a bar that measures from zero to the point for 4 has a length of 4 and can be called a 4-bar.
Next, students can apply the basic number line measurement strategy to label other points on this line. For example, if a yellow bar measures a length of 4 between the tick mark for zero and the point for 4, anywhere else on this number line, this yellow bar measures a length of 4.
So, starting at the point for 4 and adding a 4-bar to the right, measures to the point for 4 + 4 = 8.
Next, students can apply measurement strategies to check whether their initial tick mark labels are correct. For example, students who incorrectly applied a skip-counting strategy will have labeled the next tick mark 12. But, measuring a 4-bar to the right of the tick mark for 8 locates the point for 12, which is halfway between these two tick marks.
So, measurement strategies on numbers allow students to apply mathematical reasoning to justify the location and value of points and tick marks on a number line. Note that these measurement strategies will be applied and refined in each Number Line Talk in this professional learning resource.
Finally, students can apply these strategies to find the length of other measurement bars and label the other tick marks on this line.
Note that the following convention will be applied throughout Number Line Talks:
Measurement bars of a particular color will always be the same length and represent the same value on a given number line.
Grey custom bars will vary in length and be used to measure the distance from zero to different points on a number line.
But the same bar on a different line may represent a different length, based on the scale on the new number line.
Professional Learning Video
PL Video NLT 3.1 — Introduce Number Line Measurement Strategies
PL Video NLT 3.1 with captions
Daily Number Line Tasks
Teachers can display a Daily Number Line Task on the whiteboard so students can review and complete the task during a classroom transition. Each task is also available by clicking on a link to the task in the Number Line Measurement Tool (NLMT).
Then, students share strategies for measuring and labeling points on the number line. This brief activity allows teachers to review essential concepts and strategies introduced in the Number Line Talk Video and applied on the Number Line Practice Pages.
Daily Number Line Tasks—3.1 A1
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NLMT — Daily Number Line Tasks
Use the online interactive Number Line Measurement Tool to display each task. After students estimate the value of each point on the line, they can use the NLMT to share their measurement strategies with the class.
Number Line Practice Pages
The Number Line Practice Pages challenge students to apply the concepts and strategies that were introduced in the Number Line Talk and reviewed in each Daily Number Line Task.
Measurement-Bar Ruler
Students will use the rulers to measure, plot, and label points on these Number Line Practice Pages. A PDF of a set of rulers can be downloaded by clicking on the image of the Ruler PDF below the Practice Pages. Print these rulers using the same printer/copier used to print the Practice Pages. Then, use a paper cutter to cut out and trim the rulers. This process ensures that the printed size of the rulers and Practice Pages is the same so that rulers measure accurately on the Practice Pages.
PDF of Number Line Practice Pages — NLT 3.1 A1
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