The purpose of this activity is for students to analyze three different methods for solving , two of which involve decomposing an addend to make a known fact. The third method involves adding 1 to make a known fact then taking 1 away from the sum. 

Throughout this activity, students must justify and explain the work of the given characters. Students share their thinking and have opportunities to listen to and critique the reasoning of their peers (MP3).

This activity uses MLR8 Discussion Supports. Advances: listening, speaking, representing

• Invite previously identified students to share their explanations.

MLR8 Discussion Supports

• “Who can restate what _____ shared in their own words?”
• 30 seconds: quiet think time
• Consider providing students time to restate what they heard to a partner before selecting one or two students to share with the class.

The purpose of this activity is for students to find sums within 20, using addition methods flexibly based on the numbers in the problem. Students may use any method they choose. For example, for a sum such as  , students may choose to count on. For , students may apply the commutative and associative properties, and think . Students may use known facts and adjust addends as needed. Students first work independently to find each sum and then explain their method to their partner. During the Activity Synthesis, the teacher records student methods as equations.

• “What is your favorite equation? Explain how you found the sum.”
• “Did someone find that sum in a different way?”
• Share two or three equations and methods, as time allows.