The purpose of this activity is for students to solve an Add To, Result Unknown story problem. In the next activity, students will compare this story problem and a Take From, Result Unknown story problem with the same context. Students have seen expressions in previous lessons, but this is the first time that students are introduced to the term expression.

• Invite a student who showed which ducks were in the pond first and which ducks came to the pond to share. 
• “There were 5 ducks in the pond and then 4 more ducks came to swim in the pond. We can write that as ‘5 and 4’ or ‘ ’. When we write , it is called an expression.”

The purpose of this activity is for students to solve a Take From, Result Unknown story problem with the same context as the Add To, Result Unknown story problem in the previous activity. The numbers in the two problems are the same. What has changed is the action—instead of 4 ducks joining a group of 5, 4 ducks leave the larger group of 9.

• Invite a student to share their representations. 
• “There were 9 ducks swimming in the pond and then 4 of the ducks left. We can write that as ‘9 take away 4’ or ‘ ’. When we write , it is called an expression.”

The purpose of this activity is for students to choose from activities that offer practice with addition and subtraction, as well as describing and building shapes.

Students choose any previously introduced stage from these centers:

• Bingo
• Math Fingers
• Subtraction Towers
• 5-Frames
• Math Stories
• Counting Collections

• “What are your favorite materials to use during center time?”