lesson 2.8 - dividing integers

Five-Minute Check (over Lesson 2–7)

Main Idea

Key Concept: Dividing Integers with Different Signs

Example 1: Dividing Integers with Different Signs

Example 2: Dividing Integers with Different Signs

Key Concept: Divide Integers with the Same Sign

Example 3: Dividing Integers with the Same Sign

Example 4: Evaluate an Expression

Example 5: Real-World Example

Concept Summary: Operations with Integers

• Divide integers.

Dividing Integers with Different Signs

Find 51 ÷ (–3).

Answer: –17

51 ÷ (–3) = –17 The integers have different signs. The quotient is

negative.

1. A

2. B

3. C

4. D0% 0%0%0%

A. –4

B. 4

C. 27

D. 45

Find 36 ÷ (–9).

Dividing Integers with Different Signs

Answer: –11

The integers have different signs. The quotient is

negative.

Find

1. A

2. B

3. C

4. D0% 0%0%0%

A. –5

B. 5

C. 36

D. 54

Dividing Integers with Same Sign

Find –12 ÷ (–2).

Answer: 6

–12 ÷ (–2) = 6 The integers have the same sign. The quotient is

positive.

1. A

2. B

3. C

4. D0% 0%0%0%

A. –32

B. –16

C. –3

D. 3

Find –24 ÷ (–8).

ALGEBRA Evaluate –18 ÷ x if x = –2.

Answer: 9

Evaluate an Expression

–18 ÷ x = –18 ÷ (–2) Replace x with –2.

= 9 Divide. The quotient is positive.

1. A

2. B

3. C

4. D0% 0%0%0%

A. –63

B. 63

C. 7

D. –7

ALGEBRA Evaluate g ÷ h if g = 21 and h = –3.

PHYSICS You can find an object’s acceleration

with the expression , where Sf = final speed,

Ss = starting speed, and t = time. If a car was

traveling at 80 feet per second and, after

10 seconds, is traveling at 40 feet per second, what

was its acceleration?

Answer: The car’s acceleration is –4 feet per second squared.

= –4 Divide.

Replace Sf with 40, Ss with 80, and t with 10.

Subtract 80 from 40

1. A

2. B

3. C

4. D

0% 0%0%0%

A. –20ºF

B. –4ºF

C. 12ºF

D. 4ºF

WEATHER The temperature at 4:00 P.M. was 52ºF. By 8:00 P.M., the temperature had gone down to 36ºF. What is the average change in temperature per hour?

End of the Lesson

Pg 117, # 10-30 evens, 32-37all, 39

Five-Minute Check (over Lesson 2–7)

Image Bank

Math Tools

Adding Integers

Comparing and Ordering Integers

Subtracting Positive and Negative Integers

1. A

2. B

3. C

4. D

A. $40,000

B. $36,505

C. $42,500

D. $44,000

Solve the problem by looking for a pattern. Tonya gets a job that pays $35,000 per year. She is promised a $1,500 raise each year. At this rate, what will her salary be in 5 years?

(over Lesson 2-7)

1. A

2. B

3. C

4. D

0% 0%0%0%

(over Lesson 2-7)

A. 4 inches

B. 3 inches

C. 6 inches

D. 1.5 inches

Solve the problem by looking for a pattern. A ball that is dropped from the top of a building bounces 48 inches up the first bounce, 24 inches up the second bounce, and 12 inches up the third bounce. At this rate, who far up will the ball bounce on a fifth bounce?

1. A

2. B

3. C

4. D0% 0%0%0%

(over Lesson 2-7)

A. 576,000 beats

B. 9,600 beats

C. 1,152,000 beats

D. 288,000 beats

Solve the problem by looking for a pattern. Hummingbird wing-beats are about 80 per second. At this rate, how many times does a hummingbird beat its wings in 2 hours?

1. A

2. B

3. C

4. D

0% 0%0%0%

(over Lesson 2-7)

A. 3 hours

B. 4 hours

C. 4.5 hours

D. 3.75 hours

Kendra created a 5-day study schedule for her exams. The table shows the number of hours she studies in the first three days. If the pattern continues, how many hours will she study on the fifth day?