The purpose of this activity is for students to count their collection in a way that makes sense to them. Students are provided with 10-frames and counting mats to help them organize their collections. Students use appropriate tools strategically as they choose which tools help them count their collections (MP5). The purpose of the Activity Synthesis is to highlight that collections can be arranged in different ways, which will be useful in a future activity when students rearrange objects and notice that the total number of objects remains the same.

• Invite previously identified students to demonstrate how they arranged and counted their collections.
• “What do you notice about how they counted?”
• If needed, “Each person arranged their objects in a different way, but they all counted each object one time.”
• After each student shares, write or display the number and say, “There are _____ objects in their collection.”

The purpose of this activity is for students to rearrange and determine how many there are in the same collection of objects multiple times, to build their understanding that the arrangement of objects does not affect the number (MP8). As students share how many objects are in their collection, write or display the number to record their count.

• Select previously identified students who knew without recounting that the number of objects was the same to share.
• “What did you notice each time that the objects were rearranged?” (We always got the same number. The number of objects stayed the same.)
• “Count out a collection of 12 cubes.”
• Write or display the number 12.
• 1 minute: independent work time
• “How many cubes are there?” (12 cubes).
• “Arrange the cubes so they are easy to count.”
• 30 seconds: independent work time
• “How many cubes are there?” (There are still 12 cubes.)
• “Now arrange the cubes so that they are more difficult to count.”
• 30 seconds: independent work time
• “How many cubes are there?” (There are still 12 cubes.)
• “We have been rearranging objects to make them easier to count. Moving the objects around does not change how many objects there are.”

The purpose of this activity is for students to learn Stage 2 of the Tower Build center. Students practice counting out objects, counting to 20, and counting on from a given number. Students may start counting their connecting cubes from 1 each time, or they may remember how many cubes were in the tower and count on to determine the total number of cubes.

After they participate in the Tower Build center, students choose any previously introduced stage from these centers:

• Find the Pair
• Number Race
• Subtraction Towers
• 5-Frames

• Display a tower of 16 connecting cubes. 
• Count the cubes in the tower or invite a student to count the cubes.
• “Noah has a tower of 16 cubes. He rolled a 3. Is he going to win? How do you know?” If needed, ask: “Is his tower going to get to 20 cubes?” (He is not going to win. His tower will have 19 cubes.)
• “How many more connecting cubes does he need to have 20 in his tower now?” (He needs 1 more. 20 is 1 more than 19.)