Is It True or Is It False?

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SWBAT use the equal sign to show equivalent expressions. SWBAT determine whether an equation is true or false.

Big Idea

Understanding the meaning of the equal sign and finding missing addends to make equations true are the big ideas today. Students engage in conversation and activities to discuss their understanding and thinking.

Warm Up

5 minutes

I start this part of the lesson by asking the kids to sit in front of the classroom number line.  

"Today we are going to change up our Start At/Stop At routine.  We are going to use the numbers between 70 & 100."  Instead of pulling numbers out of an envelope, I am going to ask you to give me a number between  70 & 100.  Who can give me a number between 60 & 100?  Who could give me another number between 70 & 100?. I will put a green dot on the first number given and a red dot on the 2nd number."  

You should put a green dot on one stick it note and a red dot on the other.  These will be used to focus on where to start and stop.  You can also practice counting back by placing the green dot on the larger of the two numbers given.  I will call ons students to come up and pint as the class counts.

I will ask a student to point to each number as we count as a whole group.  I will continue this process as time allows.   In this case students are counting up to and back from 100, starting at any number (CCSS.Math.Content.1.NBT.A.1).  This routine is the process in which I can assure that the students are continuously working toward this standard .

Reviewing Is It True or Is It False?

20 minutes

I start by gathering the students on the carpet area and have them sit in a circle.  

"I want to review the work that we have done (all year long) on the True and False problems.  We are going to review some types that we have worked on and also look at something a little different."

I will then write the words true and false on the easel. I will make sure that everyone is still clear on the definition of true and false.

"Who can give me a statement that is true?"

I take a few suggestions and then write one or two on the board.  I then do the same for false and again write a couple on the board (see section resource).

"Who can give me some equations that are true or false?"

I gain record these on the correct side of the chart (photo in section resource).

"Now I am going to write and equation on the board.  I want you to figure out if it is true or false and prove it to me using cubes.  When everyone is done, I will ask for some of you to model who you solved it."

There is a video in the section resource (True or False) of this modeling.  In this video, the student notices that calculations are repeated in a sense that both equations need to equal 8.  This is a clear example of CCSS.MATH.PRACTICE.MP8.

"I am now going to introduce you to something a little different.  You will still be deciding if an equation is true or false, but you will have to figure out what number is missing to make an equation true."  

I then write 5+3=___+7 on the whiteboard.

"I would like you to figure out what is the missing number to make this equation true.  You can use cubes to help you solve it.  When you are done, I will ask you to explain how you figured it out."

In this case, the students are "making sense of quantities and their relationships in problem situations. (CCSS.MATH.PRACTICE.MP2)"  Making sense of these relationships is a math practice expectation, and this activity has students making sure that the quantity on both sides of the equal sign is indeed equal.

Once students have had a chance to solve it, I will ask them to share who they solved it.  I want to make sure to highlight ways of using connecting cubes to solve it.  However, will also look for students who are using relational ship thinking and/or known facts to solve the problem.  There is a video in the section resource (5+3=_+7) that exhibits the latter strategy. 

True or False Activity

15 minutes

Advanced Preparation:  Make enough copies, of the sheet in the section's resources, for each of your students.

"I will now ask that you work on your own and solve the equations on this sheet.  The first 5 are true false questions.  The last 5 are asking you to find the missing number to make the equation true."

As students are working, you will want to notice:

  • How are students determining if an equation is true or false?  
  • Do they solve the given equations?
  • Do students see relationships and use them among problems?

This activity has students looking at the equal sign and demonstrating a knowledge of it by determining if an equation is true or false and/or by finding the missing addend to allow an equation to be true. (CCSS.Math.Content.1.OA.D.7 & CCSS.MATH.CONTENT.1.OA.D.8)

Strategy Discussion

15 minutes

I gather the students back in  a circle on the carpet and then lead a discussion on how students solved some of the missing addend problems.  I call on students to model how they used cubes and also how they just solved the fact and wrote the answer above each side of the equal sign (see section resource).  In this case the students are justifying their conclusions, communicating them to others, and responding to the examples of others (CCSS.MATH.PRACTICE.MP3).

I also asked students to model with cubes, so that other students can see how this approach works. There is a video in the section resource that exemplifies this.

Mad Minute

5 minutes

I will ask the students to meet me on the carpet and hand out their sheet for today's Mad Minute exercise.  This routine was introduced in a previous lesson.  Please check out the link to get a full overview of this routine.

I want to really focus on fact fluency and build upon the students ability to solve within ten fluently (CCSS.MATH.CONTENT.1.OA.C.6).  I am going to use the Mad Minute Routine.  This is a very "old school" routine that some may question.  However, I truly feel students need practice in performing task for fluency in a timed fashion.  Students need to obtain fact fluency in order to have success with multiplicative reasoning.  Students who don't gain this addition fact fluency by the end of 2nd grade tend to struggle with the multiplicative reasoning in third.  Having this fluency also allows them to work on more complex tasks because the have the fact recall to focus on the higher level concepts.  

Continued Practice

5 minutes

I end today's lesson with a few more True or False Equations.  You will need to make enough copies for your class.  I want to have an exit ticket that reflects their understanding after our whole class discussion.

The Core expects first graders to understand the meaning of the equal sign and determine if equations involving addition and subtraction are true or false. For example, which of the following equations are true and which are false (CCSS.Math.Content.1.OA.D.7)?

  • 6 = 6
  • 7 = 8 – 1
  • 5 + 2 = 2 + 5
  • 4 + 1 = 5 + 2

I will be able to use the data from the exit ticket to see if my students have mastered this standard and design my intervention/extension strategies in future lessons.