At the opening of the lesson, Tracy Lewis re-engages students in a MARS task the students had worked on a few weeks earlier. Students are briefly asked to think about the role of a detective, since that is one of the big roles Tracy would like for them to do during this lesson.
TRACY LEWIS: A few weeks ago we did a MARS task. Okay? And we talked about a problem. So today, you actually get to be a detective. Who knows what a detective is? What is a detective? Victoria.
STUDENT: Like, they find out clues, in mysteries.
TRACY LEWIS: Okay. So a detective looks for clues, and they solve mysteries. Ka'Lon.
STUDENT: They look for something that.. describes a crime.
TRACY LEWIS: They look for something that describes a crime. So today we don't have any criminals. But we do have some mysteries.
TRACY LEWIS: So you're going to look for some math clues. What do we call math clues? D'angelo?
TRACY LEWIS: Labels... wait. All of those things fall under a category. Labels, words, what do we call all those things?
TRACY LEWIS: Evidence. So today we're going to look for, we're going to look for some evidence and we're going to see if we can solve some math mysteries. And you should be very familiar with the mystery we're going to solve. What do mathematicians use? Somebody said evidence, somebody said words, somebody said labels. Shivani?
TRACY LEWIS: Pictures! So you might see some pictures. What else might we see, Diamond?
STUDENT: Number sentences
TRACY LEWIS: We might see some number sentences...
STUDENT: Regular numbers.
TRACY LEWIS: Regular numbers, or an....
TRACY LEWIS: Might see some words, you might see some numbers, yeah. This is math, so you're going to see a.... what?
STUDENT: Um... a...a
TRACY LEWIS: There's a problem, so there's going to be a...
TRACY LEWIS: Answer, very good. Thank you guys. I'm glad you realize you were yelling. Okay, so. Here's what we're going to look at. Let's take a look. So the first thing we're going to do is, we're going to remember what it is we did, okay? So let's read the problem first. Let's read.
STUDENTS: 63 second graders are going on the field trip. 19 parents will also go. How many people are going on the field trip?
TRACY LEWIS: Okay. That was the question. Show how you know your answer is correct. That was one of the problems. Let's go down and read the second problem. Ready? Read.
STUDENTS: The apple farm is 92 miles from the school. They have traveled 58 miles so far. How many more miles do they have to go? Show how you know your answer is correct.
TRACY LEWIS: Okay, so everybody worked on this problem, and this is a sample from somebody's work. Okay? Now, if you see your work up here are you going to say, "That's mine! That's mine!"
TRACY LEWIS: No, okay. Are you going to say, "Uh! That's not right."
TRACY LEWIS: So we want to make sure that we treat our work with... what?
TRACY LEWIS: With respect. So I want you to take, oh, let's see. 30 seconds? And just look at what this mathematician did.
TRACY LEWIS: Okay, turn to a neighbor and talk. Tell them what you see. What do you see? What did they do?
STUDENT: Word pictures and models ...
TRACY LEWIS: 5, 4,
STUDENT: I see drawings.
TRACY LEWIS: 3, 2, 1. What do you see? Share out either something that you noticed or something your neighbor told you that they noticed. Jaedon?
STUDENT: Um, words?
TRACY LEWIS: Words. Where do you see words?
STUDENT: At the bottom.
TRACY LEWIS: At the very bottom. So are you looking at these words in blue? Okay. Ms. Lewis is actually going to write down "words." So we notice we have some words here. What else do you notice? Iyanna.
STUDENT: I noticed they used base 10 blocks.
TRACY LEWIS: Ah! You noticed base 10 blocks, or, uh, what category would that fall under? Is that pictures, numbers, or is that words?
TRACY LEWIS: Ah. Chaniya?
STUDENT: I see words, I see numbers.
TRACY LEWIS: You see numbers. Where do you see numbers?
STUDENT: Show how you know your answer is correct.
TRACY LEWIS: So are you looking at these numbers, these numbers? What numbers?
TRACY LEWIS: Oh. You're looking at... what do you think this is?
STUDENT: The answer.
TRACY LEWIS: The answer! Okay. So this mathematician has an answer. So there are some numbers, what else do we notice this good mathematician did? Nia.
STUDENT: They have a number sentence.
TRACY LEWIS: There is a number sentence. Okay. So, and you're noticing there are number sentences down here. Now. Let's go a little bit deeper, okay?
STUDENT: Ms. Lewis. I just noticed something.
TRACY LEWIS: Quickly. Ka'Lon.
STUDENT: I noticed that they was making the number model, but they forgot the plus.
TRACY LEWIS: You noticed that they were making a number model, but they forgot the...
STUDENT: Plus! It says 10, It's supposed to be 10 plus 10 plus 10 plus 10 plus 10 plus 10 plus 3 plus 3 plus 10. I mean- 10 plus 10 plus 10 plus 10 plus 10 plus 3 plus 10 plus 9 equals 82.
TRACY LEWIS: Oh. So you actually have a wish for this mathematician. You're running ahead of Ms. Lewis. You actually wish that this mathematician would actually make this a number...a complete number sentence? Okay.
I open this lesson by asking my students to think about the role of a detective and the use of clues in solving problems. I have taught students that mathematicians provide "evidence" -- clues to show how they came to an answer. In my 2nd grade class this includes the use of pictures, numbers, and words. My hope is that students become more thoughtful and methodical in their approach to solving word problems. Through this re-engagement experience, my goal is for students to see how important it is for the words, numbers, and pictures in their answers to relate directly to the word problem, and more specifically to the question they are to solve. I do take the time to review the appropriate behaviors and attitudes for sharing student work. This sets the tone for a professional and respectful discussion. My students are encouraged to share their ideas or those shared during a pair-share. As students move through this process, they will find it challenging to explain each other's work and come up with ideas to improve the answers given.