Lesson 3
Count to Add and Subtract
Warmup: Choral Count: Forward and Backward (10 minutes)
Narrative
Launch
 “Let’s count to 20.”
 Record as students count.
 “This time, instead of starting a 1 and counting forward, we are going to start at 10 and count backward until we get to 1. Let’s start at 10 and count backward to 1.”
Activity
 Repeat 3–4 times.
 “Let’s start at 20 and count backward to 1.”
 Repeat 2–3 times.
Student Response
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Activity Synthesis
 “In today’s lesson we will solve story problems where counting forward and backward may help you.”
Activity 1: Ride the Bus (10 minutes)
Narrative
The purpose of this activity is for students to use their knowledge of the count sequence to solve Add To, Result Unknown and Take From, Result Unknown story problems where one is added or taken away.
Advances: Speaking, Representing
Required Materials
Materials to Gather
Launch
 Groups of 2
 Give students access to connecting cubes and 10frames.
 “Today you are going to solve two story problems about people on a bus.”
Activity
 Read the first story problem.
 “Tell your partner what happened in the story.”
 30 seconds: quiet think time
 1 minute: partner discussion
 Monitor for students who accurately retell the story. Choose at least one student to share with the class.
 Reread the task statement.
 “Show your thinking using drawings, numbers, words, or objects.”
 2 minutes: quiet work time
 2 minutes: partner discussion
 Repeat the steps with the second story problem.
 Monitor for a student who can explain how they just knew the answer without making a representation.
Student Facing

There were 7 people on the bus.
Then 1 more person got on the bus.
How many people are on the bus now?Show your thinking using objects, drawings, numbers, or words.
_______________

There were 10 people on the bus.
Then 1 person got off the bus.
How many people are on the bus now?Show your thinking using objects, drawings, numbers, or words.
_______________
Student Response
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Activity Synthesis
 Invite a previously identified student to share how they solved the second story problem.
Activity 2: Singing Students (15 minutes)
Narrative
The purpose of this activity is for students to complete and solve numberless Add To, Result Unknown and Take From, Result Unknown story problems. The story problems are about adding and subtracting 1, but they do not give a starting number and therefore highlight that adding 1 to any number gives the next number in the count sequence while subtracting 1 from any number gives the previous number in the count sequence. While the kindergarten standards only ask students to solve story problems with a result of up to 10, students may choose larger numbers for their problems.
Students may benefit from having the story problems in this activity read aloud multiple times.
Supports accessibility for: Conceptual Processing, Organization
Required Materials
Materials to Gather
Launch
 Give students access to connecting cubes and 10frames.
 “Some students were singing. Then 1 more student came to sing with them. How many students are singing now?”
 “What do you notice? What do you wonder?” (Students were singing. Another student came to sing. How many students were singing? How many students are singing now?)
 30 seconds: quiet think time
 1 minute: partner discussion
 Share and record responses.
Activity
 “The story problem is missing the first number. Fill in a number and tell the story problem to your partner. Show your thinking using objects, drawings, numbers, or words.”
 4 minutes: partner work time
 Repeat the steps, including noticing and wondering, with the second story problem.
Student Facing

__________ students were singing.
Then 1 more student came to sing with them.
How many students are singing now?Show your thinking using objects, drawings, numbers, or words.
_______________

__________ students were singing.
Then 1 student stopped singing and went home.
How many students are singing now?Show your thinking using objects, drawings, numbers, or words.
_______________
Student Response
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Activity Synthesis
 Invite a student to share a story for the first problem. (There were 8 students singing. Then 1 more student came to sing with them. How many students are singing now?)
 “How many students are singing now? How do you know?” (9 because 9 is 1 more than 8. 9 comes after 8 when we count.)
 “What if there were 9 students singing and 1 more came to sing with them? How many students are singing now? How do you know?” (10. 10 is 1 more than 9.)
Activity 3: Centers: Choice Time (15 minutes)
Narrative
 Less, Same, More
 Math Fingers
 Tower Build
 Math Stories
 Which One
Required Materials
Materials to Gather
Required Preparation
 Gather materials from:
 Less, Same, More
 Math Fingers
 Tower Build
 Math Stories
 Which One
Launch
 Groups of 2
 “Today we are going to choose from centers we have already learned.”
 Display the center choices in the student book.
 “Think about what you would like to do first.”
 30 seconds: quiet think time
Activity
 Invite students to work at the center of their choice.
 10 minutes: center work time
Student Facing
Choose a center.
Less, Same, More
Math Fingers
Tower Build
Math Stories
Which One
Activity Synthesis
 “What can you do when there is a math problem or center that you’re not sure about?”
Lesson Synthesis
Lesson Synthesis
“Today we worked with story problems where one thing is added or one thing is subtracted, or taken away.”
“When you add 1 to a number, which number do you get?” (The next number when we count, the number that is one more)
“Can someone share an example of when they did that today?”
“When you take away 1 from a number, which number do you get?” (The one before the number when we count, the number that is one less, the number you say when you count backward)
Cooldown: Get off the Bus (5 minutes)
CoolDown
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