# Adding & Subtracting Positive & Negative Integers

## Overview

This is a 7th Grade Math Lesson on Adding & Subtracting Positive & Negative Integers. It is designed to be a 45-50 minute face-to-face lesson, however, some materials could be adapted for an online modality. Includes materials, and interactive activities for students to participate in.

# Adding & Subtracting Positive & Negative Integers- SUMMARY

In order to teach this lesson, teachers will need background knowledge of number lines and adding and subtracting positive and negative integers.

This lesson would be most appropriate as a follow-up lesson to introducing integers and number lines to students. Students should have some basic vocabulary (integers, positive, negative, number line) and a basic understanding of adding and subtracting.

You will also need some type of manipulatives for students to use as marking points during the lesson.

This is a lesson for 7th grade math teachers to use on adding and subtracting positive and negative integers. It includes a PowerPoint presentation, number line cards, number cards, a lesson plan, an exit ticket, a quiz, and a rubric. All of the materials could be adapted to fit the needs of diverse learners. This is designed for a 45-50 minute class period. This is designed for a face-to-face format but some of the material could be adapted for online learning as well.

Core Standard:

**Standard 7.NS.1**

Apply and extend previous understandings of addition and subtraction to add and subtract rational numbers; represent addition and subtraction on a horizontal or vertical number line diagram.

- Describe situations in which opposite quantities combine to make 0.
*For example, a hydrogen atom has 0 charge because its two constituents are oppositely charged.* - Understand
*p*+*q*as the number located a distance |*q*| from*p*, in the positive or negative direction depending on whether*q*is positive or negative. Show that a number and its opposite have a sum of 0 (are additive inverses). Interpret sums of rational numbers by describing real-world contexts. - Understand subtraction of rational numbers as adding the additive inverse,
*p*–*q*=*p*+ (–*q*). Show that the distance between two rational numbers on the number line is the absolute value of their difference, and apply this principle in real-world contexts. - Apply properties of operations as strategies to add and subtract rational numbers.

# Planning Instruction/Instruction/Assessment: Lesson Plan

Adding & Subtracting Positive & Negative Integers

Lesson Plan

Standard 7.NS.1

Apply and extend previous understandings of addition and subtraction to add and subtract rational numbers; represent addition and subtraction on a horizontal or vertical number line diagram.

Describe situations in which opposite quantities combine to make 0. For example, a hydrogen atom has 0 charge because its two constituents are oppositely charged.

Understand p + q as the number located a distance |q | from p, in the positive or negative direction depending on whether q is positive or negative. Show that a number and its opposite have a sum of 0 (are additive inverses). Interpret sums of rational numbers by describing real-world contexts.

Understand subtraction of rational numbers as adding the additive inverse, p – q = p + (–q). Show that the distance between two rational numbers on the number line is the absolute value of their difference, and apply this principle in real-world contexts.

Apply properties of operations as strategies to add and subtract rational numbers.

Materials:

PowerPoint Presentation

Number lines

Manipulatives

Number cards

Exit Ticket Worksheet

Homework Quiz

Background knowledge: Number line concept, vocabulary of positive and negative integers

Starter/Bell Ringer: (5-10 minutes)

“You earn $20 per week for mowing your neighbor’s lawn. You also earn $25 per week for completing your chores at home. You have saved $90 so far. You go shopping with some friends and want to buy new sneakers that cost $95.75. Do you have enough money to buy the shoes? Why or why not?”

-Review starter/bell ringer: ask students to give a thumbs up if they think they have enough money to buy the shoes, or a thumbs down if they don’t have enough money. Call on a few students to hear their reasoning. Explain there isn’t enough money since $95.75 is more than the $90 they’ve saved currently. They are short $5.75. This would mean they would be on the negative end of a number line because they would still owe money.

Lesson: (30 minutes)

-Show the video: https://youtu.be/DBSviXhkubg

-Discuss this concept as one way to add/subtract positive/negative numbers. This video uses direction as a way to solve problems. Review another strategy about noticing the signs, if the signs are next to each other (in the middle of the problem), and they are the same ( + + or - -), the sign becomes a +. If the signs are different (+ - or - +) the sign becomes a - .

I, WE, YOU (Whole Group Activity #1):

-Pass out number line cards and manipulative markers

-Show the first example problem: - 4 + 7 = ?

-I DO (Teacher): Teacher demonstrates starting the marker on -4 on the number line, then moves in the positive direction 7 times (counting 7 number spaces ending on positive 3), and show the answer as positive 3.

-Show the second example problem: 5 + (-8) = ?

-WE DO (whole group- teacher directed): Have students follow along with the teacher placing their marker on positive 5. -Ask students which direction we will move if it’s plus a negative 8? (Answer should be negative direction or towards the left, because the signs are different in the middle, the sign changes to a negative). Move the marker 8 spaces to the left and end on -3. The answer is -3.

-Show the third problem: 2 – (+8) = ?

-YOU DO (independent): Teacher should observe students as they independently solve this problem. They should start their marker on positive 2, and then move towards the left (negative direction) 5 spaces, landing on negative 6. The answer is -6.

-Review this problem: ask students to explain their strategy to a partner, then call on a couple of students to explain their strategy and what answer they come up with.

Whole Group Activity #2:

-Pass out number cards to each student

-Ask students to get in a line at the front of the class (or wherever you have space) with 0 as the center and creating a number line based on the number cards

-Teacher will call out problems (5-7 problems time permitting) and the students need to work together to determine where to start (which student is the starting point?) and which direction they are moving?, and where they will end up?

-Once all problems have been completed, collect number cards and ask students to go back to their seats

Wrap-up: (5 minutes)

-Review adding and subtracting positive and negative integers and techniques that can be used to solve these types of problems. Ask students to explain their strategy to a peer, then have a few students share out. Ask for any questions that weren’t answered throughout the lesson and address those.

-Assign the homework quiz for students to complete on their own time (can be adapted to be put on a Google Classroom or Canvas page)

Exit Ticket: (5-10 minutes)

-Pass out the exit ticket worksheet (5 total problems) and ask students to independently complete each problem and hand it in before leaving class.

**Adaptations/Accommodations for Diverse Learners:**

Consider pairing students with diverse needs with another student as peer support.

For the exit ticket, students with diverse needs could be asked to complete 3 of the 5 problems.

For the quiz, students with diverse needs could be asked to complete 5 of the 10 problems.

Calculators could be provided as an accommodation for students who need that type of support.

# Goals & Outcomes

Learning Intentions:

Student will be able to correctly set-up and solve problems involving adding and subtracting positive and negative integers using a number line.

Success Criteria:

Students will demonstrate understanding by showing their work using a number line on a variety of addition and subtraction problems with positive and negative integers.