This lesson helps bridge students from being able to solve missing addend and subtrahend story problems to being able to solve just the number sentence without having a story to support their understanding. This is aligned to CCSS MP2, Reason abstractly and quantitatively. Students are able to look at this abstract number sentence, and create a schema for what each of those numbers and symbols could mean in real life! This lesson also has student interact with technology and writing, two key aspects of the Common Core.
We have been looking at how to write equations to match story problems. Today we are going to look at number sentences that I wrote and see if you can think of a story that matches that equation!
Mathematicans use symbols to match their stories. When we use symbols it helps us explain what happened only using numbers.
Objective: Today your job is to be able to write a matching number sentence for a missing part number sentence.
I have a number sentence here and I am trying to figure out which story it matches. Let’s see if you can figure it out!
I'll present this number sentence on chart paper:
7 + ____ = 11
Present problem: Your job is to figure out which story problem represents this equation.
Here are the two story problems:
1. There were 7 candies in the dish. I got 11 more candies. How many candies do I have now?
2. First there were 7 candies in the dish. Then my teacher gave me some more. Now I have 11. How many candies did my teacher give me?
For formative data, turn and talk: Which one do you think matches this number sentence? Why do you think that?
Focus scaffolding questions:
To push students to start using more mental strategies, I’ll have them turn and talk to solve. Turn and talk: How many candies did my teacher give me?
Now that students have selected which story problem matches a given problem, now they are going to generate a story problem to match 14 - ___ = 12
Modeling Questions and Think Aloud:
I am going to write a story problem about ninjas. How many ninjas were there at first? How do you know?
Did more ninjas come? Or did some go away? Does the number sentence tell us how many went away?
Where would they go? How many were still there at the end?
Now I need to ask a question for the missing part: How many ninjas went away?
First there were 14 ninjas fighting. Next some of the ninjas went home. Now there are 12 ninjas left. How many ninjas went home?
Present student work time problem: 13 + ____ = 16
Let's make this story problem all about cupcakes!
Planning Partner Talk Questions:
I"ll send students to work independently and write their own story problems. After the work time, students will share their story problems with a partner: Student Share Problem. Students will prove that the story problem matches the number sentence, and I’ll share out a few exemplars with the class.
See the student work time problem here: Student Share Story Problem Writing!
Students work to write their own story problems. They get a box at the top to help them get ideas for what their problem could be about-this sparks some fun creativity! Depending on your students, you may need to have them partner talk about ways that they could show + and - with each of the nouns. What could happen to zombies so that more would come? What could happen so that some would go away?
Group A: Intervention
Students write their own story problems to match number sentences under 10. Low numbers will help support them in solving the problem.
Group B: Right on Track: See a few examples of student work. One is about Zombie.JPG and one is about Ninja Problems.JPG! You'll notice that one child left off the question. This was a common issue with this group. I had to really push them to include a question. To do this, I would give them this prompt: What part is missing? Let's use the starter "How many..."
Students write and solve their own story problems with numbers under 20.
See the two attached videos!
Group C: Extension
Same activity, with numbers under 100.
See documents for independent practice problems: IP_Writing Story Problems.
At the end of the lesson, I am going to choose 2-3 of the best story problems for students to act out. I'll tell students that we are going to send our movies to the other first grade classrooms to solve. It can be difficult to find ways to incorporate technology experiences in the younger grades-having students think about how to act in front of a camera, choosing someone to hold the camera, and even having them watch you email/upload the movie to youtube to share with other teachers are all ways to make students more aware of technology and its uses.
Students will act out their story problem on camera-it is probably best to have them act out one where you already have props available. It makes the movies more fun!