Subtracting Integers by "Walking It Out!'
Lesson 4 of 9
Objective: SWBAT modeling subtraction of Integers on a horizontal number line.
Bell Ringer (opening of lesson) Hand out Bell Ringer as students arrive in your class:
For this bell ringer, have the students grapple with each problem and come up with a strategy in which they can model the subtraction using the number line. This will lend itself to MP 1,2,4,5, and 6. Pair students up to grapple with the problems together. The ultimate goal here is to allow students the time to come up with the strategy on their own. Please see teacher guided notes for the examples given to help with students who may not be able to create a starting point.
Discussion and Student Share: 10 minutes
Briefly discuss the responses with the whole group. What are some of the strategies that the students came up with? Are the strategies reasonable? How can we use what has been shared to create strategies that work? Are their several ways to model subtraction of rational numbers on a number line?
You may refer to the number line lesson to create the large number line that may be used throughout the year.
Direct Instruction: 20 minutes
One strategy that is fun to use when helping students understand operations of positive and negative numbers on a number line is the “WALKING” strategy. This activity will get students up and active with their entire bodies. Use the notes below to teach your students the strategy. Have the students take notes on the strategy in their Interactive Math Journals. You may choose to print out the “teacher guided notes” in the resource section, or have students draw a number line for each example and hand write each example. This will be left up to you and the time you have to complete the lesson. This lesson should only take one day.
Teacher Guided Notes: These teacher guided notes were revised from the Columbus City Schools Curriculum Guide.
Student Practice: 5 minutes (MP 1,2,4)
Ok, now let’s let the students practice. Before you let them go off into their own groups to complete the student practice sheet, practice a few as a whole group. Choose 4 students to practice each example. You may use the examples given from the teacher guided notes. Have them use their created number lines to “walk out” each problem. You may also use equations of your own.
Ok, now let’s let the students practice. This student practice will lend itself to MP 1, 2, and 4. Before you let them go off into their own groups to complete the student practice sheet, practice a few as a whole group. Choose 4 students to practice each example. You may use the examples given from the teacher guided notes. Have them use their created number lines to “walk out” each problem. You may also use equations of your own.
Have students use their large number lines to solve each problem from the student classroom worksheet. Please see the resource section of this lesson for a print out version. Also, print out the blank number lines to have students illustrate what they did. They can use stick figures for their person. Use the teacher guided notes to show how this should be done.
Close of Lesson/Homework
Closing of the lesson:
Stop the lesson about 5 minutes before the period is to end. Reflect with your students about the process. Why does this work? How could you use this with directional words like east, and west? How does this compare to addition? This does not have to be formal. You can log their responses in your head and use their responses for the next day as an opener.
For the homework assignment, have students complete the above problems, along with their blank number lines. You may want to visit www.math-drills.com for further examples of problems you may choose to use. What students do not complete in the class period can be assigned for their homework. When I introduce a new lesson, I like to use their homework as their bell ringer for the opener of the next day. If you have a document camera or elmo you can have the students share their work that way, or choose a few students to “walk out” their answers using the large number line. You may want to go over each equation, or just a few to gauge understanding.