# Lesson 1: Making Measurements

Student use their yardstick to measure their heights, arm span (fingertip to fingertip with arms stretched out parallel to the floor), and other objects in the classroom. They make a line plot of their heights. They write 3 sentences comparing measurements of their groups using both addition and subtraction language. They write down the numerical equation that matches each sentence and represent their computation with a diagram on a number line (2.MD.B.6). Gallery walk? Questions about other groups’ posters?

• Task 1: measure, make a class line plot
• Task 2: Sentences comparing measurements - posters
• Task 3: “Bigger questions”: Can we stack two people to reach exactly 96 inches? Converting to feet: How many people do we need to span across the room? Across the gym? If we all stand next to each other, how far would we stretch?

## Activities:

Narrative

Students use their yardsticks to measure their heights and arm spans. They add their data on a line plot the teacher has prepared.

Launch

Students work in their maker groups from the previous lesson and they use their yardstick. Prepare a line plot on the board that students can add their data on. Explain what armspan is using a student as an example. Prepare 1x1.5 inch post-its (two colors) for students to use on the class line plot.

In the previous lesson we made yardsticks. Today you will use your yardsticks to measure your height and your arm span - that is the distance from fingertip to fingertip when your arms are stretched out as far as they go. Also measure the height or length of two other objects that you can choose.

Write your measurements for height and arm span with your initials on sticky notes. Use yellow for height and blue for armspan.

Heights and arm span between 40 and 50 inches.

Synthesis

Ask students to place their sticky notes on the line-plot  on the board - height goes on yellow above the line, armspan goes on pink below the line.

Narrative

Students write statements comparing the measurements they made within their group and represent the statements with numerical equations and using drawings on a numberline. As students work, take note of different numerical equations using addition, subtraction, and different mathematical situations (add to, take from, put together/take apart, comprare, result unknown, change unknown, start unknown, etc. see Table 1 in CCSS glossary.)

Launch

Look at the measurements from one group. Ask for a statement that compares some of the measurements and write down the associate equation (ask students for this, too). Then illustrate how to draw a number line diagram for the statement. Hand out legal sized paper for a small poster.

Write 3 statements/math problems that compare the measurements of your group.

Write equations using numbers from your measurements, +, -, = for each statement. At least one statement/equation has to use addition, at least one has to use subtraction. Illustrate each statement/equation with a number line diagram.

Make a small poster with your work.

Leilani is 47 inches tall. Her forearm is 10 inches long, which is 37 inches less than her height. 47=10+37.

Or: Leilani is 47 inches tall. Her form is in inches long. How much shorter is her forearm than her height?

OR Leilani is 47 inches tall. The chair is 23 inches heigh. If Leilani stands on the chair, the total height is 70 in.

Synthesis

After a brief gallery walk, look at posters that use different mathematical situations. For some statements/questions, ask for different equations that could also be used, e.g. 47=10+37 can be rewritten as 47-37=10. Point out how the addition and subtraction equations are related.

Narrative

In this task students use the measurements they made across the class to answer questions about linear measurement. They use addition, including repeated addition (skip counting), to add numbers within 100 using different size units -- inches, feet, yards (use same units within one problem). For some of these questions students should add the exact numbers, for other they should use rough estimates using appropriate units. The task could be done as a lengthy number talk or students could work on the different parts and come back at the end to compare answers.

Start with the first set of questions, which are using the numbers on the line graph and require addition and subtraction within 100. Then shift to the second set which should be done using estimation with feet or yards. Use skip counting by 2s, 5s, and 10s to come up with answers. Answers will be approximate.

Launch

Gather around the line plot with the class data on height and arm span.

Let’s look a little more closely at the class data - height and arm span.

• Can we stack two people to reach exactly 96 inches?
• Are there any two students who are exactly 5 inches apart in height? Are there more than two? If not, how close can we get to 96 inches?

Let’s estimate. How big are the arm spans of most students? What is that in feet or yards?

• How many people do we need to span across the room? Across the gym?
• If we all stand next to each other, how far would we stretch?

Synthesis

Notice that most students have arm spans between 4 and 5 feet. Estimate how many students it would take to span across the room. Then try it out. Use this number to estimate the distance across the room by skip counting by 4 or 5. Compare the size of the room to the size of the gym and estimate how many students it would take to span across the gym.