The purpose of this activity is for students to add and subtract within 1,000. Students organize the information about a book drive to show how many books were collected and how many were donated each month. They add and subtract to keep track of the number of books that remain at the school. When students identify information they need to know, and model a situation, using a representation such as a drawing or table, they model with mathematics (MP4).

• Invite previously identified students to share.
• “¿Qué podemos aprender de estas representaciones que no podemos ver en las notas?” // “What can we learn from these representations that we cannot see in the notes?” (We can see how many books the school had left each month.)

The purpose of this activity is for students to use addition and subtraction to answer questions about the book-drive context introduced in the previous activity. Students identify the information they need to figure out how many books the school collected in May. They then choose a number they think is reasonable and solve the problem. Students then consider what the school could do with the books they still have when the book drive is over. When students identify information they need to know to solve a problem and consider assumptions about information not given in a situation, they model with mathematics (MP4).

• Invite previously selected students to share.
• “¿Cómo sabemos que es razonable haber recolectado ese número de libros en mayo?” // “How do we know this number of books is reasonable to have collected in May?” (During the other months, the school collected about 200—300 books, and this is in that range.)
• Invite students to share different ideas for what the school could do with the leftover books.