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). 51 ÷ (–3) = –17

Answer: –17

The integers have different signs. The quotient is negative.

Find 36 ÷ (–9). A. –4 B. 4

A B C 0% D

0% D

A

D. 45

0% B

0%

1. 2. 3. 4.

C

C. 27

Dividing Integers with Different Signs Find The integers have different signs. The quotient is negative.

Answer: –11

A. –5 B. 5 C. 36 0% D

A B C 0% D C

A

0% B

0%

D. 54

1. 2. 3. 4.

Dividing Integers with Same Sign Find –12 ÷ (–2). –12 ÷ (–2) = 6

Answer: 6

The integers have the same sign. The quotient is positive.

Find –24 ÷ (–8). A. –32 B. –16

A B C 0% D

0% D

A

D. 3

0% B

0%

1. 2. 3. 4.

C

C. –3

Evaluate an Expression ALGEBRA Evaluate –18 ÷ x if x = –2.

–18 ÷ x = –18 ÷ (–2) =9

Answer: 9

Replace x with –2. Divide. The quotient is positive.

ALGEBRA Evaluate g ÷ h if g = 21 and h = –3. A. –63 B. 63

A B C 0% D

0% D

A

D. –7

0% B

0%

1. 2. 3. 4.

C

C. 7

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?

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

40 = –4

Subtract 80 from

Divide.

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

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? A. –20ºF B. –4ºF 1. 2. 3. 4.

C. 12ºF 0% D

0% C

0% B

D. 4ºF

A

0%

A B C D

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

(over Lesson 2-7)

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? A. $40,000 B. $36,505 C. $42,500 D. $44,000

1. 2. 3. 4.

A B C D

(over Lesson 2-7)

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? A. 4 inches 1. 2. 3. 4.

B. 3 inches 0%

0% D

0%

C

A

D. 1.5 inches

0%

B

C. 6 inches

A B C D

(over Lesson 2-7)

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? A. 576,000 beats B. 9,600 beats

0% D

A B C D 0% C

D. 288,000 beats

A

0%

B

C. 1,152,000 beats

1. 2. 3. 4. 0%

(over Lesson 2-7)

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? A. 3 hours B. 4 hours

1. 2. 3. 4.

C. 4.5 hours 0%

0% D

0%

C

A

0%

B

D. 3.75 hours

A B C D