SWBAT see that adding the same two numbers results in the same total, regardless of context (i.e. cubes, cards, objects) and using a strategy find the total of two quantities up to 20.

Why do 3 cubes + 4 cubes = the same amount as 3 dots + 4 dots? Through the explanation and discussion of their addition strategies, students will explain why this is true.

5 minutes

Have a student choose a number from the number card deck (1-30) and mark it on the number line. Then as a class start with the number one and rote count to the selected stop at number. This is the Start At, Stop At activity that was explained in this linked lesson:

10 minutes

*Advanced Preparation: Make a copy of Combine and Compare Assessment for each child.

I will start this task by gathering everyone in a group. I want to start with a conversation that will connect their work from the past few lessons. I remind them of all of the combining activities that they have worked on. I then explain that they are going to get a problem to solve on their own. I let them know that I want to get a sense of how they are growing in their abilities to combine and compare numbers. I then go over the problem with them and remind them to show how they figured the problem out.

* Ongoing Teacher Observations*:

As the students are working, look to see if they circle the correct set of dot cards. Do they total each pair or use another strategy to find which group has more. How are students documenting their thinking.

30 minutes

The video resource titled *Gathering Strategies* talks about what you want to be observing as your students are engaged with the Center Time Activities.

As students finish the assessment piece, they can choose from any of the following activities. Each activity has been played before and the lesson that it was introduced in has been linked below.

Dice Sums: There is a video of a student counting on while playing Dice Sums. This is an example of the types of strategies that you would be looking for.

Combine and Compare Me: There are two videos in the resource section. One is entitled Combine and Compare Me, Counting On and the Other is Combine and Compare Me, Using A Known Fact. These are two examples of the different strategies that you would be looking for.

20 minutes

*Focus of Discussion: Students Identify and share the use of a the strategy of counting all, counting on, or using known number combinations to find the sum of two quantities (CCSS.Math.Content.1.OA.A.1). Students will recognize that adding the same two quantities results in the same total regardless of item being combined.*

Bring a set of each of the combining materials used during the combining activities (cards, dice, counters). As you are calling on students, make sure to call on students who represented a variety of strategies during the center time.

I start the conversation by discussing the idea that we have been working on combining or adding two numbers together. I then ask them to think about how they would combine two dice that read 3 & 4. Ask a few students to share their strategies for solving the combinations (have counters available for modeling). There are two videos in the resource section that model a student counting all and one counting on. By sharing their strategies they are attending to precision (**CCSS.Math.Practice.MP6). **Then ask students about other situations. What if I was playing Connect 5 and pulled a 3 & 4 card, what would the total be? What about a story problem? I bought 3 red apples and 4 green apples. Hw many apples did I have?

Some students will see each problem as a new and individual problem. However, some will start to generalize 3+4 and some will even state that 4+3 is the same thing (**CCSS.Math.Practice.MP7)**. Make sure to have cubes available for students to model their thinking. There is an image int he resource section entitled end of session discussion. This image is what came from our discussion. Many of the students quickly realized that 3+4 would always equal 7 because the numbers weren't changing. One student (who has advanced number and operation skills) noted that the order didn't matter. One of the students counted on from 4 instead of 3. He quickly realized that either way it would make 7 and explained his thinking to the class.

5 minutes

Have students use lined paper to work on correct 0-9 numeral formation. At this point every numeral has been introduced.