Subtraction Number Stories- Day 1

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Students will be able to create their own number stories and represent them using one of the methods we have learned in this unit.

Big Idea

After reading If You Were a Minus Sign, students create their own number stories, by representing subtraction using pictures and possibly equations.

Problem of the Day

5 minutes

I start each math lesson with a Problem of the Day.  I use the procedures outlined here on Problem of the Day Procedures.

Today's Problem of the Day:

Kamiah has 8 pieces of candy.  She ate 5 of them.  How much candy does Kamiah have left?

I set this problem up with some structures to help the students organize their thinking.  I gave a blank number sentence frames to help the students to write their answer as an equation.  On the Notebook file, there is also a picture of a piece of candy set to Infinite Cloner.  This way the student can use it represent the problem.  If you do not have a SMART Board, you can use the PDF and manipulatives, pictures, or students' drawings.

Since we do this whole group, I have one students come up and work on this problem.  I remind the student to check their work when they are finished and have the class tell if they agree or disagree by showing a thumbs up or thumbs down.  Students also have the opportunity to share why they agree or disagree.

Presentation of Lesson

25 minutes

I start this lesson by showing the book If You Were A Minus Sign.  I remind students that a minus sign is the symbol that we put between two numbers in an equation to show that we are subtracting.  By this point, we have been working with subtraction for a few weeks, so most students are comfortable with the name and purpose of a minus sign.

We have been working with writing subtraction number sentences which are also called equations.  Today we are going to read a story about subtraction that gives some great examples of subtraction number stories.  The author and illustrator included not just words to tell the number stories but also pictures and equations.

I read the story, stopping to point out how the author and illustrator were able to represent subtraction using pictures, words, numbers and symbols.

We just got some great ideas about how to represent number stories.  Let's create our own.   

I have students give me an idea for a number story.  I illustrate it on a large piece of chart paper and write the equation to go with it.  I also model how to solve the same number story with manipulatives and on a ten frame.  I make sure to model how I want the students to complete their number story.  I include a picture that clearly represents the subtraction.  I also include the equation at the bottom of the page.  While writing equations is not required in kindergarten, it is encouraged, so I set students up with the opportunity to write an equation for their number story.

You are going to get your own "If You Were A Minus Sign" Book.  Your book has four pages.  Today I we are only going to work on the first page.  This is very much like the "If I Were A Plus Sign" books that we made, but this time we are writing subtraction number stories.  When you get your book, put your name on the cover and then put your pencil in the air.

Even though the students will be working on their number stories independently, I still have them put their name on their paper and hold their pencil in the air.  This is our routine and helps ensure that the students remember to put their name on their book.  I also like to repeat the directions one more time once they are at their seats, since some students forget what to do during that transition.  When all students have their names on their books, I remind them that we are only doing the first page today.  When they are finished, they can put their book in the basket and get their center.

I walk around and make sure that students have come up with a number story and are drawing it and writing their equations.  I have ten frames and manipulatives available for who want to use those to represent the number story.  If students use the manipulatives, I take a picture of their work and add it to their book after I print the picture.


I got the idea for this activity from Mrs. Ricca's Kindergarten.  The "If You Were A Minus Sign" student book that I am using in this lesson is available as a free download from her blog.


20 minutes

The centers for this week are:


I am not sure if or for how long I will pull groups today.  I anticipate that some students will need help with their number stories and that some may just take longer on this task than our usual independent work.  I circulate to help students with their number stories and to make sure students are engaged and do not have any questions about how to complete the centers if they have finished their number story.   If time allows, I pull groups during centers and work with them depending on the time they need (5 - 10 minutes).

Today I am focusing on subtraction with all of the groups.  While my students are doing well on our subtraction lessons and centers, as we near the end of unit assessment, I would like to observe them more closely as their work through word problems.  I verbally give the group a word problem.  I have them solve it using manipulatives and write the equation.  With students who are able to do this easily, I also have them try with drawing pictures instead of manipulatives.

Prior to clean up, I check in with each table to see how the centers are going.  My students continue to struggle with getting cleaned up quickly and quietly after centers.  I have been using counting down from 20 slowly instead of a clean up song.  Counting backwards is as critical as counting up. Students need to be able to know the number that comes before, as well as after, any given number (w/i 10, w/i 20, etc.). Counting back is a critical strategy for subtraction.

The students like to count backwards with me as they clean up and I can lengthen or reduce the clean up time based on how students are doing and how much time we have.


10 minutes

To close, I put two students' books on the document camera and project it on the SMARTBoard and have those student explain their work.  I choose one student who clearly represented subtraction in their picture and wrote a correct equation and another student who used an alternative method.  I mention positive things noticed during centers as well as something that needs to be better next time. 

I review what we did during our whole group lesson.  "Today we learned talked about subtraction number stories and working on creating our own.  Tomorrow we will continue to work on our "If I Were A Minus Sign" books by creating another number story."