The purpose of this Number Talk is to elicit strategies and understandings students have for adding one-digit and two-digit numbers. When recording students’ thinking, record using expressions that match student methods. For example, as a student is explaining , you may write .

• “How are and alike?” (They both have a value that is a multiple of 10.)
• “How are and alike?” (The ones in both expressions make more than ten, so we can compose a ten to help us add.)

The purpose of this activity is for students to learn Stage 2 of the Target Numbers center. Students add tens or ones to get as close to 95 as possible. Students take turns picking a number card, deciding to add that number of tens or ones to their starting number for the round, and writing an equation. Students start their first equation at 25 and then the sum becomes the first addend in the next round. The player who gets closest to 95 in 6 rounds, without going over, is the winner.

The purpose of this activity is for students to choose from activities that focus on adding within 100. Students choose from any of the previously introduced stages of the listed centers. They are encouraged to choose the center that will be most helpful for them at this time.

• Target Numbers
• Number Puzzles
• Five in a Row

The purpose of this activity is for students to experience different contexts in which someone adds a two-digit and a one-digit number. This helps students see math in their world. If necessary, the context of each problem can be changed to something more familiar to the students. This activity is optional because it provides practice solving story problems with numbers larger than 20, which is not an expectation of students in grade 1. 

When students create representations and expressions for the context, they develop ways to model the mathematics of a situation and strategies for making sense of and persevering to solve problems (MP1, MP4).