##
* *Reflection: Complex Tasks
Comparing Temperatures A Math and Science Comparison Part II - Section 2: Teaching the Lesson

Comparison problems are much more difficult conceptually than are part-part-whole problems. Part of the reason for this is that it is possible to solve the problem with either addition or subtraction.

Common Core Standards expect students to persevere in solving problems (MP1). They also say that students should be able to solve problems within 100 that involve adding on or taking away. Comparison problems can use both of these processing, but grasping that you can add on or subtract from to find the difference or comparison is not always easy for students to understand. These are a form of change problems where we start with an amount (the larger or smaller number) we change something (getting to the other number by adding on or taking away) and we end with the other number (the second number we were given) so for example we start at 32 degrees, we count up on a number grid or number line counting each digit as we point to 33,34,35.. as we say 1,2,3,.. to get 28 and we arrive at the second temperature or 60 degrees.

I often use the visual of 2 towers. The first tower is one amount that I have. I put the second tower or amount next to it. I show how much taller one tower is than the other. I explain to students that we want to find out how much taller (or bigger, or hotter, etc.) one is than the other. The visual of the 2 towers next to each other helps students to conceptualize the idea of comparison and then they are comfortable counting up or down to find the difference.

*The Idea of Comparisons*

*Complex Tasks: The Idea of Comparisons*

# Comparing Temperatures A Math and Science Comparison Part II

Lesson 6 of 12

## Objective: SWBAT use the data collected from measuring the temperature of ice, water, room and hand to create and solve comparison math problems.

## Big Idea: Students need to see that math has interesting, practical applications. This lesson connects math and science in a way that encourages math reasoning (MP2) and modeling (MP4).

*55 minutes*

#### Warm Up

*10 min*

Today's lesson is the second part of a lesson that combines science and math in the melting of ice and recording of time and temperature. The warm up today is a time to remind students of the work that they did at the last lesson. I ask students if they remember what we did when we had the ice in the classroom. I let students share their thoughts.

I tell them that today we will use what they recorded to write and share some math comparison problems. I pass out their science notebooks from the last lesson so they will have the data to work with. Students recorded the time it took for ice to melt and these times ranged from 4 to 18 minutes. They also recorded the temperatures of the room at 70 degrees, the ice at 32 degrees, their hands at 100 degrees and tap water at 74 degrees (some children have slightly different numbers as they each read their own thermometers).

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#### Teaching the Lesson

*15 min*

I want to make sure that students understand what a comparison problem looks like so I start today by writing a problem with them.

I tell them that when I talked to my son in Florida last night, the temperature was 80 degrees F. Here it was only 35 degrees. How could I find out how much hotter Florida was? I ask students to think about it and then give me a word problem they might ask to compare the two temperatures.

I take suggestions and write them on the board (only take 2 or 3 so it is not too lengthy or overwhelming). I ask students to look at what others suggested. Do any of them help me to know how much hotter it is in Florida? Why or why not.

Critiquing the work of someone else is a Common Core skill (MP3) that should be encouraged in second graders. If we build a climate of trust in the classroom from the beginning of the year, by accepting each contribution, by showing students when I make a mistake, by saying things like, oh that is so close, then it is possible for students to critique each other's work without fear.

Together we take the pieces of the suggestions that make sense and write a final math word problem. Now we look at our chart we made of words that help us know whether to add or subtract math street signs.docx. Which words help us here? Now I ask a student to come up and write the number sentence that goes with what we have written.

Finally I ask students to solve the math sentence in their journals. We share answers and come to consensus about how much hotter it is in Florida than here.

#### Resources

*expand content*

#### Independent Practice

*15 min*

I hand students a blank word problem form.blank word problem page.docx I ask them to create 4 problems related to the temperatures that they collected in the last lesson. I tell them they will need the words to explain the temperatures (The ice was 30 degrees and my hand was 90 degrees.), A question (How much colder was the ice?), A number sentence (90 - 30 = ___), and an answer (60).

Students work independently to write and solve their problems. I move about the room asking students to explain their thinking and to support students who are having difficulty with the idea of a comparison. I provide manipulatives as needed. I have a challenge page ready if they complete their problems before the others are done.

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#### Closing

*15 min*

I ask students to take out their math journals. I group students into groups of 4 and ask them to take turns sharing a problem and letting the others in the group solve the problem. When everyone has an answer, the person who wrote the problem checks the answers in their books. If some students did not figure it out, the writer explains how to get the answer.

I circulate around the room to listen to what the students are doing, and to provide support as needed.

*expand content*

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- UNIT 1: What and Where is Math?
- UNIT 2: Adding and Subtracting the Basics
- UNIT 3: Sensible Numbers
- UNIT 4: Sensible Numbers
- UNIT 5: Everything In Its Place
- UNIT 6: Everything in Its Place
- UNIT 7: Place Value
- UNIT 8: Numbers Have Patterns
- UNIT 9: Fractions
- UNIT 10: Money
- UNIT 11: The Numbers Are Getting Bigger
- UNIT 12: More Complex Numbers and Operations
- UNIT 13: Area, Perimeter and More Measurement
- UNIT 14: Length
- UNIT 15: Geometry
- UNIT 16: Getting Ready to Multiply
- UNIT 17: Getting Better at Addition and Subtraction
- UNIT 18: Strategies That Work

- LESSON 1: Where is the Question
- LESSON 2: Playing Teacher - Checking Our Work
- LESSON 3: Estimation - an introduction
- LESSON 4: Using Models to Add and Subtract
- LESSON 5: Comparing Temperatures a Science and Math Exploration Part I
- LESSON 6: Comparing Temperatures A Math and Science Comparison Part II
- LESSON 7: Checking Subtraction
- LESSON 8: Introducing the Addition Algorithm
- LESSON 9: Addition Algorithm Rote or Understanding
- LESSON 10: Adding Repetitive Sets of Numbers
- LESSON 11: Adding and Subtracting in Columns
- LESSON 12: Getting Better At Addition and Subtraction Final Project