Students will explore adding integers through the use of the TI-Navigator's Number Line in Activity Center. Through this exploration, students will be encouraged to look for patterns. At the end of the exploration the class will be able to establish the rules for adding integers.
Before the Activity
Configure the Activity Center as shown in the attached PDF file.
Note the Exploration Problems given in the PDF file.
Print out the student recording sheet in the attached PDF file for your class.
During the Activity
Have students log in to TI-Navigator and select Activity Center.
Start the Activity and then do a Screen Capture to explain all of the options on the calculator screen if your students are not already familiar with Number Line in Activity Center.
Have students submit their answers as they finish the problem.
Discuss the vectors shown from student responses and the numerical answers students submitted.
As a class, fill in the student recording sheet with the problem, the answer, the actual operation used, and the sign of the answer.
Stop the Activity, Clear Activity Data, Configure with the next problem from the ten given ones on the PDF file.
Start Activity and continue this process through the first four problems. After the fourth problem, pause to look for patterns.
Students should note that each time the operation was addition and that the sign stayed the same as the signs of the numbers in the problem.
Use problems five through nine in Activity Center. Continue filling out the student recording sheet with each problem.
After the ninth problem, pause to look for patterns.
These will be more difficult for students to see. They should recognize that the operation used was actually subtraction and that the sign of the number with the largest absolute value is the sign of the answer.
Use problem ten to round out all of the possibilities.
After the Activity
As a class, write the rules for adding integers according to the patterns you were able to discover in this exploration.
Remind students that they can always use the number line to add integers but with large numbers this becomes cumbersome. However, if they ever forget the rules, they can always make up a simple problem that would fit on a small number line to help remind them of what the rules are.