Lesson 5 of 8
Objective: SWBAT define equal. SWBAT determine if two equations are equal.
Setting Up the Learning
This standard addresses students' understanding of the equal sign. This is crucial to their later success in algebra, and is yet another way that Common Core focuses on strong foundations for first graders. A common misconception in equality is that students assume if it "looks wrong", then it can't be true. So 5 = 2+3 is false because 5 is on the "wrong" side.
To help students relate to the equals sign, I use a basketball metaphor and the concept of being tied. All of my students have had experiences with keeping score before, and this makes a very hefty math topic surprisingly intuitive!
I'll have 3 number sentences written on the board, but covered up. See attached image for example! Mystery Number Sentence Chart
3=3, 2+1=3, 2+1=2+1
We have been learning about the <, > and = symbols. Today we are going to apply what we have learned to comparing two number sentences.
This is important because you will use these symbols in first grade, second grade...and all the way to college! They help us compare numbers without having to write a lot of words.
Objective and Hook:
I have 3 mystery number sentences here. As we discuss what it means to be equal, we are going to come back to these number sentences over and over. Your thinking job is: Are these number sentences equal?
Today, our job is to see if two things are tied, or equal. When you play basketball with your friends, you might end the game and you are tied. It means you both got the same amount of points.
Present problem 1: I have a story to tell you about a time I played basketball with Mr. Johnson. We are both really good basketball players. We were playing and when the game ended, I had 3 points. Mr. Johnson had 3 points. Were we tied? Yes! What symbol do we use when 2 things are the same amount? An equal sign! OK-so I had 3, and he had 3. So 3=3.
- Briefly remind kids of the alligator mouths “This reminds me of when we used the alligators to compare numbers. We used the equal when the number was the same!”
- Uncovers the first mystery number sentence. Do we agree that 3=3? Are they tied? Are they equal?
Present Problem 2: Now during our second game, I really wanted to beat Mr. Johnson. First I got a 2 pointer, than I got a 1 pointer. What number sentence could I write to match the points I got (2+1). Mr. Johnson got just one 3 pointer. T writes 3.
- Partner Talk: Were we tied at the end of the game? How do you know?
Restates: So we both had 3 in all. 2+1 is 3. And Mr. J had 3. So we were tied. I can write the number sentence 2+1=3. (Uncover the number sentence)
Problem 3: So far we have been tied both times! I have one more game and I want to see if our scores were tied. In this game, I scored 1 point, then I scored 2 more points. ( Record number sentence- 1+2) Mr. J. scored 2 points and then he scored 1 more point. (Records 2 + 1).
- Partner talk: Are we tied? Do we have the same number of points? How do you know?
Restate: Since we are tied, I can use an equal sign here. 1+2=2+1
See attached image for an example of the anchor chart we used.
Game Rules and Practice
You are going to play Double Compare to help you practice determining if two number sentences are equal.
- Each player draws 2 cards. Each card has a number on it.
- Each player adds their own numbers together.
- Ask the question: Are we tied? Are we equal?
- Record on the recording sheet.
For the recording sheet, I’ll have students circle >, < or =. This is a great way to extend their understanding of "Greater Gator". The standard (1.NBT.3) focuses only on 2 digit numbers, however this lesson allows students to expand how they are able to use these inequality symbols to other mathematical statements.
The RecordingSheet.pdf is attached. Just write in the >, < and = sign!
I’ll have students practice a couple of rounds and I’ll model recording. See Game Rules Chart for an example!
See Student Explanation of one student explaining her thinking about a whole group round of Double Compare!
This is a good example of ways to consistently integrate MP3, Construct viable argument and critique the reasoning of others. Instead of having the student leader explain everything, she calls on someone to explain part of her thinking. Always asking your kids to explain WHY helps them get very comfortable with the dialogue, even when you challenge their thinking or ask clarifying questions.
Game Time! Partner Practice
Students play the game we practiced with a partner and record the number sentences on their recording sheet. Then they circle >, < or =.
Most students will play the game as intended, however below are examples of intervention and extension opportunities.
Intervention: Only use number cards 5 and under. This will insure students never work with sums of more than 10.
Extension: Take off the pictures completely. Most students by this point will naturally count on or use another strategy to add. But for an extra challenge, take away the picture part of the card to insure that they aren't counting all of the pictures!
This game is a great way to incorporate addition fluency, which is now explicitly stated within the standards, into other parts of your math block. Students are practicing number fluency while thinking about algebraic principles!
You can get the cards I used for the game here.
See attached video for an example of 2 students playing this game and explaining their thinking! Another great example of students using MP3, "Construct viable arguments and critique the reasoning of others".
To preview what we will be doing for the next couple of lessons in the unit, I'll present students with 2 number sentences and tell them they came from the game.
I'll present them without any card support, so students have to think to solve both sides on their own.
Focus Question: Are these number sentences equal or not? How can you prove it?
9 + 4 __ 10 + 3
Students solve on white boards if time. If not, I'll have 2 students come up and each solve one side.