Grade 6 Integer Addition and Subtraction

Introduction

Integer Addition and Subtraction is an important Grade 6 math skill because students are moving from simple answers toward explaining how the math works.

In this lesson, students use models, real questions, worked examples, practice problems, and two online quizzes to build confidence with integer addition and subtraction.

What Is Integer Addition and Subtraction?

Integer Addition and Subtraction means using place value, operations, and equations to reason accurately with numbers.

The goal is not only to get the answer. Students should be able to show the idea, explain the strategy, and check whether the answer makes sense.

Understanding Integer Addition and Subtraction

Before solving, students should slow down and decide what each number, shape, unit, or label represents.

Read the question carefully and identify what is being asked.
Choose a model, equation, table, or diagram that matches the situation.
Solve one step at a time and keep units or labels attached.
Use the answer explanation to check that the result makes sense.

Visual Models

Visual Model 1

Question: Use the number line to find $5+(-8)$.

Visual Model 1

A. $-13$
B. $-3$
C. $3$
D. $13$

Why it works: Start at $5$ on a number line and move $8$ units left. The result is $5+(-8)=-3$.

Answer: $-3$

Visual Model 2

Question: Which chip model shows $-4+6$? (Red chips = $-1$, Blue chips = $+1$)

Visual Model 2

A. Model A; answer is $2$
B. Model B; answer is $2$
C. Model A; answer is $10$
D. Model B; answer is $8$

Why it works: $-4+6$: use 4 red and 6 blue chips. Pair and remove red-blue pairs. Result: 2 blue chips remaining, so $-4+6=2$.

Answer: Model A; answer is $2$

Worked Examples

Example 1

Question: A bank account starts at $$250$. After a withdrawal of $$100$, what is the new balance?

Example 1

A. $$150$
B. $$350$
C. $$100$
D. $-$150$

Starting balance: $250$.
Withdrawal is $-100$.
So $250+(-100)=150$.

Answer: $$150$

Example 2

Question: The temperature at noon was $5°\text{C}$. By evening, it dropped $12°\text{C}$. Use the thermometer to find the evening temperature.

Example 2

A. $7°\text{C}$
B. $-17°\text{C}$
C. $17°\text{C}$
D. $-7°\text{C}$

Start at 5° and drop (subtract) 12°: $5+(-12)=-7°$.

Answer: $-7°\text{C}$

Example 3

Question: Show $-5+(-3)$ on a number line.

Example 3

A. Starts at $-5$, ends at $-8$, sum is $-8$
B. Starts at $-5$, ends at $-2$, sum is $-2$
C. Starts at $0$, ends at $-8$, sum is $-8$
D. Starts at $-5$, ends at $-3$, sum is $-3$

$-5+(-3)=-8$.
Start at $-5$ and move 3 units left, landing at $-8$.

Answer: Starts at $-5$, ends at $-8$, sum is $-8$

Real-World Word Problems

Problem 1

Question: A hiker starts at elevation $1{,}200$ feet and climbs to $1{,}850$ feet. What is the change in elevation?

A. $650$ feet
B. $-650$ feet
C. $3{,}050$ feet
D. $1{,}200$ feet

Why it works: Change in elevation: $1{,}850-1{,}200=650$ feet.

Answer: $650$ feet

Problem 2

Question: A student uses a chip model with red chips = $-1$ and blue chips = $+1$. Starting with 5 red and 4 blue, they remove 3 red. What is the result?

Problem 2

A. $-9$
B. $-2$
C. $9$
D. $2$

Why it works: After removing 3 red chips from 5 red and 4 blue, we have 2 red and 4 blue remaining. This represents $-2+4=2$.

Answer: $2$

Common Mistakes

Rushing before identifying what the numbers represent.
Choosing an operation that does not match the situation.
Dropping labels, units, or context from the answer.
Skipping the estimate or reasonableness check.

Strategy Tips

Underline the question being asked.
Use a model before jumping to computation.
Write an equation that matches the story or picture.
Explain the final answer in a sentence.

Practice Questions

Question 1

What is $-7+3$?

A. $-10$
B. $-4$
C. $4$
D. $10$

Question 2

A golf player has a score of $-5$ (5 under par). She then plays another hole and her score drops by $2$ more strokes. What is her new total score?

Question 2

A. $-7$
B. $-3$
C. $3$
D. $7$

Question 3

Which number line correctly shows $-4+6=2$?

Question 3

A. Arrow goes from $-4$ right $6$ to $2$
B. Arrow goes from $-4$ left $6$ to $-10$
C. Arrow goes from $0$ right $6$ to $6$
D. Arrow goes from $4$ right $6$ to $10$

Question 4

Using a chip model where red chips represent $-1$ and blue chips represent $+1$, what is the sum?

Question 4

A. $-1$
B. $1$
C. $5$
D. $-5$

Question 5

What is $2+(-2)$?

Question 5

A. $-4$
B. $0$
C. $2$
D. $4$