Lesson 1

• “Let’s count to 80.”
• Count to 80 1–2 times as a class.

• “Now, start at the number 10 and count to 20.”
• Count on from 10 to 20.
• Record as students count.
• Repeat 3–4 times starting with other numbers within 20.

• “We counted and recorded the numbers from 10 to 20. Find and point to the number 11. Tell your partner how you know you found the number 11.”
• Repeat 2–3 times with other numbers 11–20.

The purpose of this activity is for students to count their collection in a way that makes sense to them. Students may use the counting mat or 10-frame to organize objects as they count. Students use appropriate tools strategically as they choose which tools help them count their collections (MP5). As students share how many objects are in their collection, write or display the number to record their count. 

If there is additional time, invite students to count more than 1 collection of objects.

• Each student needs a collection of 11–20 objects.

• Groups of 2
• Give each student a collection of objects and access to 10-frames and a counting mat.
• “How many objects are in your collection?”

• 5 minutes: independent work time

If students recount the group of objects when asked “how many?”, consider asking:

• “Can you tell me how many objects there are without counting them again?”
• If needed, demonstrate counting the group of objects and after saying the last number, ask “What does the number ___ tell us?”

• “Tell your partner how you figured out how many objects are in your collection.”
• Invite 2–3 students to share how they counted their collection.
• After each student shares, display the number and say, “There are _____ objects in their collection.”
• “In the next activity we will share different ways that we counted our collections.”

The purpose of this activity is for students to describe different methods that help them count collections of objects. Consider adding visual cues to the chart created in this activity and leaving it displayed for students to refer to throughout the unit. When students explain how they could count the disorganized cubes, they attend to precision in counting accurately (MP6).

• Create a pile of 4 connecting cubes to display.
• Create a pile of 13 connecting cubes to display.
• Students need the collections of 11-20 objects from the previous activity.

• Groups of 2
• Give students access to 10-frames and counting mats.
• Display 4 connecting cubes in a scattered arrangement.
• “How many cubes are there? How do you know?” (There are 4 cubes. I can just see 4. I counted 1, 2, 3, 4).
• 30 seconds: quiet think time
• 1 minute: partner discussion
• Share responses.
• Display 13 cubes in a pile.
• “How many cubes are there?” (We can’t see how many there are. There are a lot.)
• 30 seconds: quiet think time
• 1 minute: partner discussion
• Share responses.

• “What can we do to figure out how many cubes there are?”
• 1 minute: quiet think time
• 1 minute: partner discussion
• If needed, ask “How would you count this collection of cubes?”
• Share and record responses on a chart.

• “We talked about and wrote down many different ways that we can count collections of objects. Switch collections with your partner and figure out how many objects are in your new collection. If it is helpful, you can choose to count your collection in one of the ways that we talked about.”
• 3 minutes: independent work time

The purpose of this activity is for students to learn stage 2 of the Number Race center. Students practice recognizing and writing numbers 11–20 as they roll a connecting cube onto the mat and trace the number that it lands on. To support their developing number recognition, students can match the symbol on the number mat to the symbol on the recording sheet. Students continue rolling and tracing until one number “wins” (all of the numbers in the column are traced). After students have traced all of one number, they can finish tracing the rest of the numbers. Students can use different colors or writing utensils during this center. In a future variation of this center, students will write the numbers instead of tracing them.

After they participate in the center, students choose from any stage of previously introduced centers.

• Subtraction Towers
• 5-frames

Students will choose from these centers throughout the section. Keep materials from these centers organized to use each day.

• Gather materials from:
  • Subtraction Towers, Stage 1
  • 5-frames, Stages 1 and 2

• Groups of 2
• Give each student a recording sheet and access to colored pencils or other writing utensils. Give each group of students a number mat and a connecting cube.
• “We’re going to play Number Race with numbers 11–20.”
• Display the recording sheet and number mat.
• “What steps do we take to play Number Race with our partner?”
• 30 seconds: quiet think time
• 30 seconds: partner discussion
• Share responses.
• If needed, review the steps for Number Race with students.
• “Take turns with your partner. During each turn, roll the cube and trace the number on the recording sheet. Play until you’ve traced all of one number. That number is the winner.”

• 8 minutes: partner work time
• “Now you can choose another center. You can also continue playing Number Race.”
• Display the center choices in the student book.
• Invite students to work at the center of their choice. 
• 10 minutes: center work time
• If time, invite students to choose another center.

• Invite a student to share their completed recording sheet.
• Point to and say each number. Invite students to chorally repeat each number.
• “Which numbers did they roll more than 3 times?”
• “Which numbers did they roll less than 4 times?”