Operations with Integers

## Teacher Lesson Plan

### Go to Student Page

This activity is aligned to NCTM Standards - Grades 6-8: Number and Operations, Problem Solving, and Communication and to California Mathematics Standards Grade 7: Number Sense #1.2.

#### California Mathematics Standards to be addressed in this lesson:

Number Sense
1.2 Add, subtract, multiply, and divide rational numbers (integers, fractions, and terminating decimals) and take positive rational numbers to whole-number powers.
Specifically:
subtracting integers
multiplying integers
dividing integers

#### Assessments

1. Written work with real world examples of integer problems.
2. Quiz - adding and subtracting integers.
3. Quiz - multiplying and dividing integers.

#### Set-up

Download a copy of Math Stars (Macintosh) or (PC) by Roger Clary. Send in the shareware fee. Load your copy of Math Stars on the computers you have available.

#### Introduction

If you have a One Computer Classroom then this would be a method for using Math Stars. If you are able to make use of a Computer Lab then I still would recommend using this method to introduce the software before having the students work individually.

I use this technique to introduce integers in general.

1. Using one computer with a large display (either on a television monitor or using a video projector) boot Math Stars.
2. Provide half sheets of paper and instruct students to write their student header at the top.
3. Select one student to run the program using the following settings:
• Type in a name for Player One.

• Select Let's Play
• There are three categories with settings including Functions, Timer and Number. To introduce integers, select Addition, 10 seconds and Allow Negative Numbers. If students have been working with integers, select other settings under Functions and Timer.

• Select OK and this screen will appear:

• Select Begin and the problems will appear on the screen.

4. The student who is operating the computer should not enter their answer immediately so that the students in the class have time to record their answers.
5. After completing one round, have a class discussion. Here are some possible questions:
• Give examples of four different types of integer addition problems. The idea is that they will say for example, 4 + 3, -4 + -3, -4 + 3, and 4 + -3.
• Looking at the numerical examples, can you make up a real-world problem to match? The idea is that they will relate this to temperature or money or walking forward/backward.
6. Have the students write a real-world scenario for each of the four different examples of integer addition problems. Examples:

• 4 + 3
The temperature is 4 degrees. It warms up by 3 degrees. What is the temperature now?
• -4 + -3
The temperature is 4 degrees below zero. It gets colder and the temperature drops 3 degrees. What is the temperature now?
• -4 + 3
The temperature is 4 degrees below zero. It warms up by 3 degrees. What is the temperature now?
• 4 + -3
The temperature is 4 degrees. It gets colder and the temperature drops 3 degrees. What is the temperature now?
7. Now select another student to work the computer to be displayed and run through more rounds of Math Stars.

#### Computer Lab

Once the students have been introduced to integers, if a computer lab is available they can work individually or in pairs. Math Stars has the option to have two players work at one time. The only difference is that the students select Math Stars (head-to-head) and enter both of their names as players.

#### Extensions/Suggestions

1. To continue reinforcing the mathematics, have a short drill in class using one computer but rather than writing the answers, prompt the students to respond orally to each problem.
2. Extend the use of Math Stars to include subtraction, multiplication, division and/or a mixture of all four operations.
3. Use the More Options feature to change the orientation of the problems from vertical to horizontal or any other options that are available.