The purpose of this activity is for students to work with problems that involve multiplication within 100 where one factor is a teen number. This is the first time students have solved multiplication problems with numbers in this range, so they should be encouraged to use the tools provided to them during the lesson if they choose (MP5). Students should also be encouraged to use strategies and representations from the previous section.

As students are paired to create posters, try to include a variety of approaches for students to see during the Gallery Walk in the next activity, such as:

• Count by the teen number.
• Count by the single digit number.
• Use the distributive property to decompose the teen number to multiply in parts.
• Use the distributive property and place value understanding to decompose the teen number into tens and ones to multiply in parts.

• Ask students to explain why we can use multiplication to solve all of the problems in this activity.
• Display the posters around the room.

The purpose of this activity is for students to consider what is the same and what is different about the ways that students solved problems involving multiplication of a teen number. Students may notice representations that were used, as well as different strategies that were used to find the total in the problem. The important thing is that students see a variety of ways to represent and solve the problem.

• Give students a chance to ask questions they have about any posters.
• “What is the same about the thinking shown on the posters?”
• “What is different about the thinking shown on the posters?”