The purpose of this Warm-up is to elicit the idea that there are many sums within 10, and students may already know many of these sums. This will be useful when students identify sums they know and don’t know in a later activity.
“This table shows all the sums that you need to know by the end of the year. As you noticed, there are some you already know.”
“Tell your partner 3 sums you know.”
Activity 1
Standards Alignment
Building On
Addressing
1.OA.C.6
Add and subtract within 20, demonstrating fluency for addition and subtraction within 10. Use strategies such as counting on; making ten (e.g., ); decomposing a number leading to a ten (e.g., ); using the relationship between addition and subtraction (e.g., knowing that , one knows ); and creating equivalent but easier or known sums (e.g., adding by creating the known equivalent ).
The purpose of this activity is for students to explore sums within 10. Students pick their favorite sum as an entry point to the next activity in which students sort the sums into those they know and those they don’t yet know.
MLR8 Discussion Supports. During group work, invite students to take turns sharing their responses. Ask students to restate what they heard using precise mathematical language and their own words. Display the sentence frame: “I heard you say . . .” Original speakers can agree or clarify for their partner. Advances: Listening, Speaking
Launch
Groups of 4
Display the addition chart from the Warm-up.
“You are going to choose your favorite sum from the addition chart. For example, my favorite sum is because I like sums of 10.”
Activity
“Pick 1 or 2 sums that are your favorite. Explain why they are your favorite using drawings, numbers, or words.”
4 minutes: independent work time
“Share your favorite sums with the other students in your small group.”
4 minutes: small-group discussion
Monitor for students who wrote equations with addends of 0 or 1, equations with the same addend twice, or sums of 10.
Pick your favorite sum.
Write an equation to show the value of your sum:
Show why it is your favorite using drawings, numbers, or words.
Student Response
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Advancing Student Thinking
Activity Synthesis
Invite previously identified students to share their favorite sums.
“Why is this sum a favorite of yours?”
Activity 2
Standards Alignment
Building On
Addressing
1.OA.C.6
Add and subtract within 20, demonstrating fluency for addition and subtraction within 10. Use strategies such as counting on; making ten (e.g., ); decomposing a number leading to a ten (e.g., ); using the relationship between addition and subtraction (e.g., knowing that , one knows ); and creating equivalent but easier or known sums (e.g., adding by creating the known equivalent ).
The purpose of this activity is for students to identify which sums within 10 they know and which they don’t know yet. Sums that students know from memory or that they have a quick mental method to find should be categorized as “got it.” Consider giving each student two bags or envelopes to keep their cards separated for ease of practice. Label one bag “Got It” and the other “Not Yet.” As students know more sums from memory, they can move them to the “Got It” bag.
This activity provides an opportunity for formative assessment on students’ fluency with addition within 10. Use discretion in asking students to explain their answers, as some students will simply know the sums—or count on so quickly in their head that they may not be able to explain how they got it. These students should not be required to draw a picture to represent the sum.
Look for students who know sums such as , , , and , as these tend to be the most challenging for students and will be discussed during the Lesson Synthesis. After that Synthesis, collect the student workbook page to formatively assess sums students did not know.
Students will use the addition cards in a future lesson.
Engagement: Develop Effort and Persistence. Support metacognition and motivation by drawing attention to the end-of-year fluency goal. “By the end of this year, we will know many sums and differences within 10. Let’s see which sums within 10 we know today, so we know which ones we can keep practicing.” Supports accessibility for: Social-Emotional Functioning, Attention
Launch
Groups of 2
Give each student scissors and a set of cards.
“First, cut out your cards and mix them up.”
5 minutes: independent work time
“We saw that you already know the value of a lot of sums. Let’s try a few together. Give me a thumbs up when you know the value of the sum.”
Display .
“How do you know this one?” (Adding 1 is quick. It’s just 1 more than the number.)
“This is a sum that many of us know right away. Any sum that you know the value of quickly is placed in the ‘got it’ pile.”
Display .
“For this sum, I might have to count on my fingers from 5. This is a sum that I can figure out, but it takes just a bit longer. When it takes you a little longer to find the value of the sum, place that card in the ‘not yet’ pile.”
Activity Synthesis
“What patterns do you see in the sums you know? (I know all the +1 sums. I know all the sums of 10.)
“Which sums are more difficult to find?” (The sums that are + 4 or + 5 that do not make a 10 are harder.)
“By the end of the year, you are going to be able to quickly tell the value of the sum for all the addition expressions within 10.”
Lesson Synthesis
Display three common “not yet” expressions. Consider showing expressions such as , , and .
“Today we looked for sums we know, so we know which sums to continue practicing. Some students know . What is a method you can use to help a friend who doesn’t know the value of this sum yet?” ( is the same as . They can start at 5 and count on 3 quickly, 5...6, 7, 8.)
Highlight and record 2–3 student methods for more challenging sums. These methods can be displayed in the classroom for students to refer to later in this section and unit.
Standards Alignment
Building On
Addressing
Building Toward
1.OA.C.6
Add and subtract within 20, demonstrating fluency for addition and subtraction within 10. Use strategies such as counting on; making ten (e.g., ); decomposing a number leading to a ten (e.g., ); using the relationship between addition and subtraction (e.g., knowing that , one knows ); and creating equivalent but easier or known sums (e.g., adding by creating the known equivalent ).
