SWBAT generate equivalent expressions for a number. SWBAT use numbers and standard notation to record. SWBAT use known strategies to solve story problems.

So many things to do and so little time to do them in. Students will have the opportunity to challenge their addition and subtraction skills through a variety of activity choices.

5 minutes

Using the established Quick Flash Routine have the students replicate the cube patterns that are flashed to them. In this case you will use cards D, E, & F (the cards are available in the linked lesson). After the students have created the patterns, ask them to explain how they saw each group of cubes and how that helped them replicate the image.

I want my math practice to encourage students to Construct viable arguments and critique the reasoning of others. The idea being that mathematically proficient students understand and use stated assumptions, definitions, and previously established results in constructing arguments. I want them to have the ability to make conjectures and build a logical progression of statements to explore the truth of their conjectures. I also want them to be able to analyze situations by breaking them into cases, and can recognize and use counterexamples, and to justify their conclusions, communicate them to others, and respond to the arguments of others (**CCSS.Math.Practice.MP3**). This activity is an example what this would look like in 1st grade. The students are comparing and contrasting ideas, finding other ways of looking at an idea, and understanding that their are multiple ways to look at the abstract image.

I have included a video in the resource section that demonstrates students explaining the way they saw the group of cubes.

20 minutes

I begin this part of the lesson by having the students try and guess the Number of the Day. I will write a number line on the whiteboard that ranges from 1-25 and give them two clues about the number. Then I will ask them to ask other questions to obtain more information about the number.

******Some other possible questions might be: *Does it have one digit? Does it have two digits? Is there a 5 in it? Is there a 1 in it?* You want to encourage students to ask questions that will narrow the set of possible numbers.

**"I want you to use figure out what Today's Number will be. I am going to give you two clues. One clue is that the number is greater than 4. The other clue is that it is less than 17."**

I will write the two clues as >4 and <17. I am using this as an opportunity to use the notation for greater than and less than. This was something that I introduced at the beginning of the year.

**"Who has another question they can ask to get more information about the unknown number?"**

I continue to do this until the number has been found. Today's number is 8.

I then ask the students "How can you represent eight?" I remind them that we can write the number 8, the word eight, and draw 8 dots. Then I take suggestions from them. I had included a picture of the poster we made from this discussion (see the section resource).

40 minutes

The students will have a choice of a variety of addition and subtraction activities. All but one of them has been introduced in previous lessons.

1. Number of the Day: Using the handout in the section resource, the students find multiple ways of representing the number eight. They should be encouraged to use numbers and equations to represent their thinking. There is also a video in the resource section that demonstrates a student explaining their thinking during this activity. The Core Standards expect math students to model their thinking with mathematics. The idea being that mathematically proficient students can apply the mathematics they know to solve problems arising in everyday life, society, and the workplace. In early grades, this might be as simple as writing an addition equation to describe a situation (**CCSS.Math.Practice.MP4**). The students have an opportunity to demonstrate an understanding of the equal sign because they can notate 8+2=10 or 10=8+2 (CCSS.Math.Content.1.OA.D.7).

2. Story Problems: The students should continue working on the the problems they started two lessons ago. For those who finish and are ready for more challenging problems, I have included a new set of Challenge Problems in the section resource. It is expected that, by the end of the year, 1st grade students can use addition and subtraction within 20 to solve word problems involving situations of adding to, taking from, putting together, taking apart, and comparing, with unknowns in all positions, e.g., by using objects, drawings, and equations with a symbol for the unknown number to represent the problem (CCSS.Math.Content.1.OA.A.1). These problems are allowing you to gain an idea of how each student is developing with their progress toward this standard.

3. Subtraction Bingo: This activity was introduced in the lesson Ideas on Subtraction. Go to the Center Time section of the linked lesson to see the description and the resources needed. There is a video of a student playing this game in the section resource.

4. Dice Subtraction: This activity was introduced in the lesson Ideas on Subtraction. Go to the Center Time section of the linked lesson to see the description and the resources needed. There is a video of a student playing this game in the section resource.

Activities 3 & 4 both have students working on subtraction fluency. The Core Standards expect first graders to relate counting to subtraction and subtract within 20, demonstrating fluency for subtraction within 10 (CCSS.Math.Content.1.OA.C.5 & CCSS.Math.Content.1.OA.C.6). These two activities allow for the opportunity to work on these skills and take steps toward fluency.

5 minutes

I want to continue to have students solve a variety of addition and subtraction facts as well as equations with missing addends and complements of 10. This activity is another opportunity to work with these concepts and use standard notation.