1-5 Adding Integers

Warm UpWarm Up

Lesson PresentationLesson Presentation

Problem of the DayProblem of the Day

Lesson QuizzesLesson Quizzes

1-5 Adding Integers

Warm UpGraph each number on a number line.

1. –5 2. 7

3. –4 4. 0

–5 –4 –3 –2 –1 0 1 2 3 4 5 6 7

1-5 Adding Integers

Problem of the Day

Start at 0 on a number line. Move 5 units left and 3 units right. Where are you on the number line?

–2

1-5 Adding Integers

Learn to add integers.

1-5 Adding Integers

To add a positive number move to the right. To add a negative number move to the left.

Helpful Hint

Additional Example 1A: Using a Number Line to Add Integers

Use a number line to find the sum.

(–6) + 2

2

–6

You finish at –4, so (–6) + 2 = –4.

–6 –5 –4 –3 –2 –1 0 1 2 3 4 5

1-5 Adding IntegersAdditional Example 1B: Using a Number Line to Add

IntegersUse a number line to find the sum.

–3 + (–6)

–3

–6

You finish at –9, so –3 + (–6) = –9.

–9 –8 –7 –6 –5 –4 –3 –2 –1 0 1 2

1-5 Adding Integers

Check It Out: Example 1A

Use a number line to find the sum.

(–3) + 7

7

–3

You finish at 4, so (–3) + 7 = 4.

–6 –5 –4 –3 –2 –1 0 1 2 3 4 5

1-5 Adding Integers

Check It Out: Example 1B

Use a number line to find the sum.

(–2) + 4

4

–2

You finish at 2, so (–2) + 4 = 2.

–6 –5 –4 –3 –2 –1 0 1 2 3 4 5

1-5 Adding Integers

1-5 Adding Integers

Additional Example 2: Using Absolute Value to Add Integers

A. 1 + (–2)

Add.

1 + (–2)

2 > 1; use the sign of 2. –1

B. (–8) + 5

(–8) + 5

8 > 5; use the sign of 8. –3

Think: Find the difference of 1 and –2 .

Think: Find the difference of –8 and 5 .

1-5 Adding Integers

Additional Example 2: Using Absolute Value to Add Integers

C. (–2) + (–4)

Add.

(–2) + (–4)

Same sign; use the sign of the integers. –6

Think: Find the sum of –2 and –4 .

1-5 Adding Integers

Check It Out: Example 2

A. 3 + (–6)

Add.

3 + (–6)

6 > 3; use the sign of 6. –3

B. (–4) + 1

(–4) + 1

4 > 1; use the sign of 4. –3

Think: Find the difference of 3 and –6 .

Think: Find the difference of –4 and 1 .

1-5 Adding Integers

Check It Out: Example 2C

C. (–6) + (–7)

Add.

(–6) + (–7)

Same sign; use the sign of the integers. –13

Think: Find the sum of –6 and –7 .

1-5 Adding Integers

Additional Example 3: Evaluating Expressions with Integers

Evaluate c + 4 for c = –8.

c + 4

Replace c with –8.

8 > 4; use the sign of 8.

(–8) + 4

–8 + 4 = –4

Think: Find the difference of –8 and 4 .

1-5 Adding Integers

Check It Out: Example 3

Evaluate d + 7 for d = –3.

d + 7

Replace d with –3.

7 > 3; use the sign of 7.

(–3) + 7

–3 + 7 = 4

Think: Find the difference of –3 and 7 .

1-5 Adding Integers

Additional Example 4: ApplicationMeka opened a new bank account. Find her account balance after the first four transactions listed below.

Deposits: $200, $20 Withdrawals: $166, $38

Use a positive sign for deposits and a negative sign for withdrawals.

200 + 20 + (–166) + (–38)

Use the Associative Property to group integers with same signs.

(200 + 20) + (–166 + –38)

Add integers within each group.220 + (–204)

220 > 204; use the sign of 220.16

Meka’s account balance after the first four transactions is $16.

1-5 Adding Integers

Check It Out: Example 4Michael opened a new bank account. Find his account balance after the first four transactions listed below.

Deposits: $175, $95 Withdrawals: $133, $65

Use a positive sign for deposits and a negative sign for withdrawals.

175 + 95 + (–133) + (–65)

Use the Associative Property to group integers with same signs.

(175 + 95) + (–133 + –65)

Add integers within each group.270 + (–198)

270 > 198; use the sign of 270.72

Michael’s account balance after the first four transactions is $72.

1-5 Adding Integers

Standard Lesson Quiz

Lesson Quizzes

Lesson Quiz for Student Response Systems

1-5 Adding Integers

Lesson QuizAdd.

1. –7 + (– 7) 2. 15 + (–9) + (–2) 4–14

Evaluate each expression for the given value

of the variable.

3. 13 + r for r = –15 4. 2 + b + (–9) for b = –6–2 –13

5. On Monday, a local dog shelter had six dogs.

By Friday they had found homes for three, but

took in two more. Then how many dogs were in

the shelter? 5 dogs

1-5 Adding Integers

1. Add –19 + (–29).

A. 48

B. 10

C. –10

D. –48

Lesson Quiz for Student Response Systems

1-5 Adding Integers

2. Add 27 + (–16) + (–9).

A. 2

B. 20

C. 34

D. 52

Lesson Quiz for Student Response Systems

1-5 Adding Integers

3. Evaluate the expression for the given value of the variable.

74 + r for r = –46

A. –74

B. –46

C. 28

D. 120

Lesson Quiz for Student Response Systems

1-5 Adding Integers

4. Evaluate the expression for the given value of the variable.

8 + z + (–8) for z = –8

A. 8

B. –8

C. –16

D. –24

Lesson Quiz for Student Response Systems

1-5 Adding Integers

5. In January, Tina had 9 pens. By March, she had given 3 pens to her friends. In the meanwhile, her dad bought her 4 pens. Then how many pens did Tina have?

A. 8 pens

B. 9 pens

C. 10 pens

D. 16 pens

Lesson Quiz for Student Response Systems