The purpose of this activity is for students to add 2 two-digit numbers within 100, without composing a ten, in any way that makes sense to them. 

Monitor for and select students with the following approaches to share in the Activity Synthesis:

• Break both addends into tens and ones, add tens and tens, and then add ones and ones.
• Start with one of the addends, add the tens from the second addend, and then add the ones from the second addend.

When sequencing student approaches, consider inviting students to share from the most common approach to the least common approach used during the activity to help them make sense of different ways to use place value to add 2 two-digit numbers. Aim to elicit both key mathematical ideas and a variety of student voices, especially students who haven't shared recently.

During the Activity Synthesis, each step of students’ thinking is represented with connecting cubes and equations.

• Invite previously selected students to share in order from the most common approach to the least common approach. Record or display their work for all to see.
• If students have not done so, record student thinking with connecting cubes and equations as they explain their approach.
• Connect students’ approaches by asking:
  • “¿En qué se parecen estos métodos? ¿En qué son diferentes?” // “How are the methods alike? How are they different?” (They both got 68. They used connecting cubes. They worked with tens and ones. The first person broke both numbers apart into tens and ones. The other person broke 45 into tens and ones but didn’t break 23 into tens and ones.)
  Connect students’ approaches to the learning goal by asking:
  • “¿Cómo las ecuaciones , ,  se relacionan con lo que hizo __________?“ // “How do the equations , ,  match ___________’s work?” ( shows the tens from both numbers being added together. shows the ones from both numbers being added together. shows the total when you put all the tens and ones together.)
  • “¿Cómo las ecuaciones ,  se relacionan con lo que hizo __________?“ // “How do the equations ,  match ___________’s work?” (They started with 23, added the 4 tens from 45, and then added the 5 ones from 45.)

The purpose of this activity is for students to analyze two different representations of addition methods and identify the equations that match each method. One of the representations shows adding tens and tens and ones and ones. The other representation shows counting on by tens and ones.

• Display Elena’s work and the matching equations.
• “¿Cómo corresponden estas ecuaciones al dibujo?” // “How do these equations match the drawing?” (You can see she added the 60 and the 20. Then she added the 3 and the 5.)
• “¿Cómo describirían la forma en la que Elena encontró la suma?” // “How would you describe how Elena found the sum?” (She added tens and tens, then ones and ones. Then she added the total number of tens and ones together.)
• Display Andre's work and the matching equations.
• “¿Cómo corresponden estas ecuaciones al dibujo?” // “How do these equations match the drawing?” (He started with the 63 and then added 20. Then he added the 5.)
• “¿Cómo describirían la forma en la que Andre encontró la suma?” // “How would you describe how Andre found the sum?” (He started with 63 and added the tens. Then he added the ones.)

The purpose of this activity is for students to learn Stage 5 of the Five in a Row center. Students add within 100, without composing a ten. Partner A places a paper clip on the gameboard to cover one number in each gray row. They add the numbers and place their color counter on the sum. Partner B moves one of the paper clips to a different number in the same row, adds the numbers, and places their color counter on the sum. Students take turns until a player gets 5 counters in a row or the board is filled. Two gameboards are provided, one where students add a one-digit and a two-digit number and one where they add a two-digit and a two-digit number. For this activity, students work with the gameboard with one-digit numbers.

The gameboards will be used again in upcoming lessons. Consider copying on cardstock or laminating for future use. 

• “¿Cómo decidieron cuál clip mover?” // “How did you decide which paper clip to move?” (I looked at the gameboard and saw which numbers I needed to cover. I tried to find numbers that would have that sum.)