The purpose of this activity is for students to determine the missing number and tower from the set of 1–10. Students may use the written numbers or the towers or start counting from 1 to determine which are missing. Students may create a cube tower with the same number of cubes as the tower next to the missing tower, and put 1 more cube on or take 1 cube away. Students may use the existing numbers and determine which number is 1 more or 1 less (“6 is 1 more than 5. 6 is 1 less than 7.”) 

In the Synthesis, students will discuss how they thought about 1 more or 1 less to find the missing number. When students relate the count sequence, via cube towers or numbers, to 1 more and 1 less, they are using a vital structure of the count sequence (MP7).

• “¿Qué estás intentando descubrir?” // “What are you trying to figure out?”
• “¿Puedes construir una torre que vaya en este lugar?” // “Could you build a tower that fits in this spot?”

• Display the towers and numbers in order from 1 to 10 with 9 missing.
• “¿Qué número falta? ¿Cómo lo saben? // “What number is missing? How do you know?”
• “¿Usaron los números o las torres como ayuda para descubrir lo que faltaba?” // “Did you use the numbers or the towers to help you figure out what was missing?”
• Invite previously selected groups to share how they used 1 more or 1 less with towers or numbers to figure out what number was missing.

The purpose of this activity is for students to identify the number that is 1 less or 1 more than a given number. Students build cube towers and write numbers to match. Students can then find 1 less or 1 more, using the number or the cube towers for support.

• Invite a student to share a tower and number they recorded.
• “Escoge una torre de cubos. ¿Qué números puedes usar para mostrar 1 más y 1 menos?” // “What cube towers and numbers can we record to show 1 more and 1 less?”

The purpose of this activity is for students to choose activities that offer practice with number and counting concepts

• Math Stories
• Math Libs
• Number Race

• “¿Qué les gustó de las actividades en las que trabajaron hoy?” // “What did you like about the activities you worked on today?”