SWBAT measure lengths using a single unit. SWBAT compare lengths to determine which is longer.

Bill Murray called it "Baby Stepping" but today we will be student stepping. The students will measure 8 different lines using their own feet!

5 minutes

I gather the students on the carpet and have them face the number grid. I am using a 101-199 number grid, to work on rote counting bigger numbers. The CCSS expect that students can count to 120, starting at any number less than 120. This activity allows for you to check for students both meeting and exceeding the standard (CCSS.Math.Content.1.NBT.A.1).

*"We are going to count from one number to another. Sometimes we will count forwards and sometimes we will count backwards. I am going to put this green card in front of the number 101. Who can tell me a number we should put this red card in front of?"*

** I take a student response and then ask another student to come up and place the card in front of the suggested number. This allows me to choose someone who I want to check and see if they can find the given number. **

I then go over where we will start and stop and ask if we are counting up or down? I also go over the reason why we don't say the word "and" when we are reading big numbers. There is a video in the resource section of this introduction and discussion of why we don't say "and."

I continue with a few rounds (as time allows).

40 minutes

Advanced Preparation: You will need to put tape down on the floor. I have included a video to show you what it looks like. They should vary in length and each would should be labeled a different number (1-8).

*"As you can see there are 8 different tape lines ( I call them floor strips) on the floor. Floor strip one is right here (point to it) and it goes from my desk to the big black chair. Floor strip two is right here (point to it) and it goes from the table to the black chair. Which distance do you think is longer, Floor strip 1 or 2?"*

I take a few predictions and ask them to explain their thinking.

**"What Could I do if I wanted to know for sure? If I wanted to know which one is longer, how could I figure it out?"**

Again, I take responses. Being that we had been using tiles and cubes (in other lessons) to measure, inevitably the suggestion to use one or both of them will one up.

*"We could use the inch tiles but it would take quite a few of them and it would also take a long time to count so many tiles. When mathematicians have something long to measure, they usually use units that are bigger. Adults like to use their feet. Have you ever seen someone do this?" When you use your feet today, we will call them "Student Steps."*

** "Like using tiles, we must follow the same techniques when we are feet. Who can remind us of the techniques we need to follow when measuring? (See video Review of Measuring Techniques in section resource)"**.

** "Let's use student steps to measure Floor Strip Two. Who can model this for us? I call on a volunteer or two."** There is a video (Modeling With Student Steps) in the section resource. While students are modeling, I want to point out the appropriate techniques that they are using.

*"Now you are going to work in teams to measure the different strips. You will each need a copy of the recording sheet 9see section resource). While one person is measuring a strip, the other will be counting the steps too. This way you can double check your work and make sure that your count was accurate. After you measure it,you will record how many student steps you counted when you measured, Then you will record that amount on the sheet. Next, your partner will repeat the activity but with his/her own feet. Once you have a measurement, you will circle which strip was longer (see recording sheet and/or student examples in resource section).*

*I want you and your partner to go through and answer each set of questions. When you are finished, we will discuss our findings."*

The CCSS expect first graders to: express the length of an object as a whole number of length units, by laying multiple copies of a shorter object (the length unit) end to end; understand that the length measurement of an object is the number of same-size length units that span it with no gaps or overlaps.* (CCSS.Math.Content.1.MD.A.2)*.

It is important to make sure that students don't confuse the idea of measuring with their on feet compared to that of a standard foot. You can choose to define this now or wait an address any misunderstandings that come up. I prefer the latter of the two.

10 minutes

Once the students are finished, I call them back to the carpet with their recording sheets. I have created a chart for the discussion that will be filled out as we talk about our results (see section resource).

** "If you remember, the first question I asked was which strip was longer, Strip 1 or Strip 2? Which one was longer? I want you to use your measurement results to answer the question."** As students respond use tally marks on the chart to record which one each student found was longer. You should then repeat this process for the other three comparisons.

If any disagreements come up, you should have that student remeasure as the class checks how he/she used their feet to find the distance. This way the students can check each other to see if he/she is doing it the correct way. Mathematically proficient students try to communicate precisely to others. They calculate accurately and efficiently, express numerical answers with a degree of precision appropriate for the problem context. In the elementary grades, students give carefully formulated explanations to each other (**CCSS.Math.Practice.MP6**).

Note: You are not focusing on the numerical amounts but rather which tape had a greater distance.

10 minutes

Students should complete the combinations sheet in the section resource. I ways to check in with how the are doing with their backward counting, 10 facts, and finding missing addends for an addition equation.

The sheet is in the section resource.

I continue to add this type of activity at the end of the lesson to review concepts that have been covered throughout the year. It is the expectation that 1st graders will determine the unknown whole number in an addition or subtraction equation relating three whole numbers. *For example, determine the unknown number that makes the equation true in each of the equations 8 + ? = 11, 5 = _ – 3, 6 + 6 = _ (CCSS.Math.Content.1.OA.D.8)*.