Reviewing the Equal Sign
Lesson 7 of 19
Objective: Students will be able write a subtraction equation using the equal sign.
Problem of the Day
I start each math lesson with a Problem of the Day. I use the procedures outlined here on Problem of the Day Procedures.
Today's Poblem of the Day:
I gave my dog 5 bones. He buried 3 of them in the backyard. How many bones does he have left?
I set this problem up with some structure to help the students organize their thinking. I give a blank number sentence to encourage students to write an equation. I also include a bone set to infinite cloner. If you do not have a SMART Board, you can use the PDF and manipulatives, pictures or students drawings.
Since we do this whole group, I have one student come up and do this problem. I remind the student to check their work when they are finished and have the class tell if they agree or disagree by showing a thumbs up or thumbs down.
Presentation of Lesson
I then give two students papers with numbers on them. I have them stand in the front of the room. I hand another students a paper with a minus sign and place that student in between the others.
This is a minus sign. It is the symbol that we use to show that we are subtracting. We read this as 5 minus 3. This is kind of like a sentence that we use in reading, but it is a sentence with numbers. A number sentence is called an equation. Just like a sentence in reading, the parts needs to be in the correct place for it to make sense. We need to keep the minus sign between the two numbers that we are subtracting. We put the answer to the right. In addition we call the answer the difference. Between the two numbers that we are subtracting and the answer to the problem is where we put the equal sign. That tells us that when we subtract it is the same as this number.
Count the pictures. Write the numbers and equal sign to complete each equation.
The first thing the directions tell you to do is count the pictures and write the number to complete each equation. You also need to write the equal sign. For the first few questions, the equal sign is there and you just need to trace it.
We work through this paper together. On the last question the students need to write in the minus sign and the equal sign. I model this for the students and point out how important it is that these symbols are in the correct place since they mean different things. I walk around and make sure that students are correctly counting and writing their equations. When students are finished with their paper, they can put it in the basket and get their center.
The centers for this week are:
- Addition Word Problems (I used a Lakeshore Read and Solve Word Problems Center. You can also use these Addition Word Problem Cards that I made.)
- Easter Egg Addition (Available free from Teachers Pay Teachers)
- Goldfish Graphing (Available free from Teachers Pay Teachers)
- Piggy Bank Addition Mat (Available free from Mrs. Ricca's Kindergarten)
- Sweater Math Match-Up (Available free from Teachers Pay Teachers)
I quickly circulate to make sure students are engaged and do not have any questions about how to complete the centers. Because of the trouble during our addition unit, I decided not to introduce any subtraction centers this early in the subtraction unit.
I pull 3 groups (5-10 minutes depending on need). We are working on writing equations in all groups. I verbally give the group an equation. I have them write it and then solve it using manipulatives. With students who are able to do this easily, I also have them try with drawing pictures instead of manipulatives.
Prior to clean up, I check in with the other tables to see how the centers are going. My students have been struggling with getting cleaned up quickly and quietly after centers. Lately I have been using counting down from 20 slowly instead of a clean up song. Counting backwards is as critical as counting up. Students need to be able to know the number that comes before, as well as after, any given number (w/i 10, w/i 20, etc.). Counting back is a critical strategy for subtraction.
The students like to count backwards with me as they clean up and I can lengthen or reduce the clean up time based on how students are doing and how much time we have.
To close, I put a student's paper on the document camera a project it on the SMART Board and have that student explain their work. I have the class read the equation using the words minus and equals. I mention positive things noticed during centers as well as something that needs to be better next time.
I review what we did during our whole group lesson. "Today we learned about the symbol that is used in an equation to show that the two sides of the equation are the same or equal. Tomorrow we are going to start a series of lessons where where we practice subtracting from a given number!"