The purpose of this activity is for students to discuss different ways to solve a three-addend story problem in which none of the addends can be combined to make 10 without being decomposed. Students solve the problem in a way that makes sense to them. Some students may build each number separately on the 10-frames and see both are filled. Some students may manipulate the numbers and think . Different methods for solving are highlighted in the Synthesis. It is important that the teacher represents student thinking, so that these methods are visible to all.

When students make sense of the story problems and connect the quantities in the story to an equation, they reason abstractly and quantitatively (MP2).

• Invite previously identified students to share.
• “What did they do to find the sum?”
• Record each method with an equation.

In this activity students solve three-addend story problems within 20. Students use methods and representations that make sense to them. When students connect the quantities in the story to an equation, they reason abstractly and quantitatively (MP2). They think strategically and may either choose to use a double 10-frame or decompose and compose the numbers in a way that helps them see the sum as 10 and some ones (MP1, MP5).

• Invite students to share their method for each problem. 
• Record each method with an equation.