Lesson 5

The purpose of this How Many Do You See is for students to subitize or use grouping strategies to describe the images they see. The images include 10-frames to elicit students' work when adding within 20 and encourage students to think about composing a ten by counting on, which will be the focus of activities later in the lesson.

• Groups of 2
• “How many do you see? How do you see them?”
• Flash the image.
• 30 seconds: quiet think time

• Display the image.
• “Discuss your thinking with your partner.”
• 1 minute: partner discussion
• Record responses.
• Repeat for each image.

• “How are the second and third images the same and different?” (In the third image all of the 10-frames are full, but in the second they are not.)

The purpose of this activity is for students to add a one-digit number and a two-digit number in a way that makes sense to them. As students add, they may apply their learning from previous lessons to count on, make a new ten, apply the commutative property, or add ones and ones.

Monitor and select students who use the following methods to share in the synthesis:

• Start with 47, count on 8 (\(47 + 8\))
• Start with 47 and decompose the 8 into 3 and 5 to make a new ten (\(47 + 3 + 5\))
• Add the ones (\(7 + 8\)), then add on the tens (\(15 + 40\))

In addition to these different methods, monitor for different ways that students represent their thinking (connecting cubes, drawings, equations). Students who use connecting cubes or base-ten drawings may physically compose a new unit of ten. This representation will be explored further in future lessons, but can also be used in this activity synthesis when sharing methods that show adding the ones, then adding the tens.

• Groups of 2
• Give students access to connecting cubes in towers of 10 and singles.

• Read the task statement.
• 3–5 minutes: independent work time
• “Share your thinking with your partner.”
• 3 minutes: partner discussion
• As students work, consider asking:
  • “Where is the 47 in your representation?”
  • “Where is the 8 in your representation?”
  • “How did you determine the sum?”

If students count on to find the sum, consider asking:

• “How did you find the sum?”
• “How could you use 10-frames or connecting cubes to find the sum without counting by one?”

• Invite previously identified students to share in the order listed in the activity narrative. If students only share equations, represent their thinking with connecting cubes or base-ten drawings.
• “What is the same about how each student found the sum? What is different?” (They all got 55. The first one started at 47 and counted on by ones. The second one added 3 to 47 to make 50 then added the 5 ones. The last one added the ones first then added the tens.)

The purpose of this activity is for students to practice adding a one-digit number and a two-digit number in a way that makes sense to them. Students may choose to use methods shared in the previous activity. Give half of the class one-digit numbers and the other half two-digit numbers. Students pair up to create a sum with a two-digit number and a one-digit number. In some problems, the sum will require composing a ten when adding ones to ones. Monitor for students who share ways they make a new ten with connecting cubes or drawings to share in the synthesis.

When students choose a method to add based on the pair of numbers they are adding, they make use of structure and apply regularity in reasoning (MP7, MP8). This could mean counting on when the 1-digit number is small, adding the ones when there is no new ten, and adding on to make a ten if needed.

• Create a set of cards from the blackline master for the class.

• Groups of 2
• Give students access to connecting cubes in towers of 10 and singles.
• Give half of the students one-digit number cards and half of the students two-digit number cards.
• Display the student workbook page with the practice round.
• “Each person has a card with a number on it. You will find a partner and find the sum of your two numbers. One student should have a one-digit number and the other should have a two-digit number. Let's do one round together.”
• Invite one student with each kind of card to share their number.
• “Find the sum of the numbers. Show your thinking using drawings, numbers, or words. Then write an equation that shows the value you found.”
• 2 minutes: independent work time
•  Share an equation that could be used. 
• “Now we will all play a few rounds.”

• “Find a partner and find the sum of your numbers.”
• 5 minutes: partner work time
• “Switch cards with your partner and find a new partner.”
• Repeat as time allows.
• Monitor for students whose sum:
  • does not require composing a new ten.
  • requires composing a new ten when adding ones and ones.

• Invite previously identified students to share.
• After each student shares, ask “Why did you choose this method?” (Since I was adding only 3, I could count on quickly. The number 9 would take too long to count on so I broke it apart to make a new ten and then added the rest.)

The purpose of this activity is for students to solve story problems that require adding a two-digit number and a one-digit number with composing a ten. This activity offers additional practice using methods discussed in the previous activities, while giving context for adding these quantities. Students share different times in their lives that they have added or seen others add quantities like those they have been adding. 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. 

• Groups of 2
• Give students access to connecting cubes in towers of 10 and singles.
• Read the first problem aloud.
• “What is this story about? How can we find out how much money Tyler’s teacher collected?” (It is about money for a field trip. We can add \(37 + 7\).)
• “We need to add some more ones to a two-digit number in order to find out how much money Tyler’s teacher collected. When do you need to add numbers or quantities like this in your life? When do you see others do this?” (My mom adds up how much things cost at the store. The teacher adds groups of kids on the playground to see if we are all there. When I get new stuffed animals, I add up how many I have altogether. When a team scores more points we add them to the points they already had.)

• “Solve the problem to find out how much money Tyler’s teacher collected. Then solve the next problem.”
• 3 minutes: independent work time
• 2 minutes: partner discussion
• Monitor for students who use connecting cubes or base-ten drawings to solve.

• Invite previously identified students to share their method for each problem.