Subtraction Act it Out!
Lesson 3 of 6
Objective: SWBAT represent subtraction problems with quantities to 10 by acting them out.
Each day we begin our math block with an interactive online calendar followed by counting songs and videos.
We do calendar on Starfall every afternoon. This website has free reading and math resources for primary teachers. It also has a “more” option that requires paying a yearly fee. The calendar use is free. A detailed description of Daily Calendar math is included in the resources.
Counting with online sources: Today we did counting practice to reinforce the counting skills. We watched two to three number recognition 0-10 videos (one to two minutes each) because some of my students students were still struggling with identifying numbers correctly in random order. We watched"Shawn the Train" and counted objects with him to refresh our memories on how to count objects to ten and to reinforce one to one counting. Since we have started the second quarter of the school year, we added to today's counting practice: counting to 20 forward and back, counting by tens to 100 and counting to 100by ones to get a jump on our end of the year goals.
I made the direct instruction for this lesson quite simple. My goal for this lesson is to make subtraction accessible and fun.
I read the story, Five Little Monkeys and use counting cubes to demonstrate the math on each page as I read. If you don't have this book, you can access it on YouTube.
Then we review what we already know about addition and subtraction.
First we review the subtraction and equal (same as) signs.
Me: What is this? (holding up the subtraction sign)
Students: Subtraction sign!
Me: What does it mean?
Students: To get less (or to lose some)
Me: What is this? (holding up the equal sign)
Student: Equal sign!
Me: What does it mean?
Students: Same as
Me: Very nice, (showing signs) this is a subtraction sign. It means to have less or lose some. This is an equal sign and it means the same as. Let's practice using these two signs in some equations.
I use Fruit Shoot from Sheppard Software on the ActivBoard so we can solve subtraction problems together. I model the concept first. I then choose names from the name stick jar to come up and click the answers we decide on as a group.
You could use flash cards or write problems on a board if you don't have access to the technology needed for Fruit Shoot.
For guided practice we use our bodies. I have the kids go to their tables and I tell the table captains that when we act out our subtraction problems that they are to designate who has to move away from the group each time (those are the subtracted students). These only go to quantities of 5 because each table has five students. Adjust accordingly for your own classroom or make small groups in various parts of the room.
I say the first number sentence (equation):
5 - 2 = ? Each table captain asks 2 students to step away from the table.
Me: Okay, so 5-2 is the same as?
Me: Great! (I ask the students to return to their tables). Here's problem number 2. 5 - 4 = ? The table captains ask 4 students to step away from each table. I say, "5 - 4 = ?"
Me: Okay, last one for now. 5 - 3 =? The table captains again ask some of the students to step away from the tables. I say, "5 - 3 = ?"
For this next part I break the kids into three groups of 8 and have one student be an extra (I usually choose one of my highest students because he or she doesn't need extended practice on this concept. I also choose new captains for each group. Now we practice subtracting from 8. "8-2=?"
The group captains ask two students to step away from each group. They count how many are left (It's not as obvious as the problems done in groups of five). "What is 8-2 the same as?"
We do two more random subtraction problems using groups of 8 and then move to independent practice.
For this activity I have helpers give each student a bag of 10 snapping counting cubes. The cubes in the bags are one color and I ask the helpers to make sure that people sitting close together do not have the same color. This prevents the cubes from being mixed up and keeps students accountable for their materials. I use subtraction flashcards to present the problems.
The students build towers of quantities up to 10 and then remove cubes to subtract from the towers. We do the first one together.
Me: You are going to use your cubes to act out subtraction problems. Let's practice the first one together. 6 - 2 = 4 (best practice is to have the equation written out on a card and hold it up for the visual learners). Take 6 blocks out of your bag and build a 6 tower. When you're done, hold your tower up in the air.
Once everyone is holding up a 6 tower, I say, "The problem is 6-4. We have a 6 tower, now what should we do?"
Students: Take away 4 blocks.
Me: Why are we taking 4 blocks away?
Random Student (name picked from name-stick jar): We take 4 blocks because it says minus 4 so we have to take it away.
Me: Okay, lets all take 4 blocks off of our tower and see how many we have left. (Students remove 4 blocks) How many blocks do we have left?
Me: So let's read the entire problem including the answer. Altogether (teacher and students): 6 - 4 = 2. We continue practicing together for two more subtraction equations. 9 - 5 = __ and 10 - 3 = __
Next we independently practice on the floor and I monitor what each student is doing. Any students struggling to grasp the concept or the steps of subtraction, I pull them up to the front with me and form a small group to continue guided practice while the rest of the group continues with independent practice.
The independent practices when we have gone through all of the cards or when we run out of time.
The students are given a simple subtraction page and their bag of cubes. They solve the problems by acting them out with their cubes and recording the solutions as they solve them. I use Subtract worksheet for the Exit Ticket.
As they turn them in, I group them in piles of Meets, Approaches, and Falls Far Below. They were scored as follows:
Meets: misses 0 or 1
Approaches: misses 2
Falls Far Below: misses more than 2
Meets continue with lessons as planned. Approaches meet with me one on one for a quick check-in to determine what misconception led them to the wrong answers.
FFB meets with me in a small group for direct instruction and re-teach.