Show the students of two 5 dot cards at the same time. Follow the Quick Flash Routine (http://www.cc.betterlesson.com/lesson/501226/quick-flash). Ask the students to determine the total number of dots. Repeat the activity with a 5 dot card and a 4 dot card. These cards can be found in the resources section on the side of this page. You should download the sheet and cut out the cards.
I start with having the students gather in a group on the carpet. I start by singing the song Old McDonald (see singing song in resource section). I am doing this to get their attention and set a context for the story. After the song, I tell them that the animals have all decided to come to our classroom to play. I then tell the following story: There was 1 pig. Then 2 cows came. Then a group of 3 chickens. Then 4 dogs and 5 cats. I then ask a few students to tell me which animals and how many of them were coming to the classroom. After that, i tell the kids that they will be working on their own to try and figure out how many animals are coming to our classroom. I will also tell them that they will need to show me on paper how they figured it out. By asking them to document their thinking and labeling their work, I am asking them to attend to precision (CCSS.Math.Practice.MP6).
I will give each child a blank piece of paper and ask them to find a spot to work on the problem.
Students should work individually, but encourage them to share with one another their strategies for solving 1+2+3+4+5 and record their work. This will require the students to model their work with mathematics (CCSS.Math.Practice.MP4). The students will be recording the numbers of animals that they added together. I ask them to solve a story problem using an addition strategy (CCSS.Math.Content.1.OA.A.1). The students are also solving a problem that requires them to solve a problem that adds three whole numbers with a sum less than 20 (CCSS.Math.Content.1.OA.A.2). I have included two video clips of students working on the problem (see the resources on the side of the page).
As students are working, you should observe the following:
How do students represent the number in each group?
How do the students find the total number of animals?
How do students document their work?
Gather all of the students back together in a circle with their posters. Have a student volunteer to share their solution and how they recorded their work. I have included three different video examples of this "share-out" in the resource section. Underneath each video is a photograph of each piece of work (in case you can't see it in the video). Then ask the group who else solved it that way. Then ask is their another way that someone solved it? This discussion allows students to compare their work to others and ask questions about approaches shared (CCSS.Math.Practice.MP3). After the discussion, model the equation 1+2+3+4+5=15 for the students. This will be a great way of modeling a mutl-addend equation for the students.
Have students complete the Dot Sums worksheet. The sheet is located on the resource section on the side of the page.