Msm1 fl ch11_07

11-7 Dividing Integers

Warm UpWarm Up

Lesson PresentationLesson Presentation

Problem of the DayProblem of the Day

Lesson QuizzesLesson Quizzes


Warm UpFind each quotient.

1. 18 ÷ 2 2. 42 ÷ 7

3. 56 ÷ 8 4. 24 ÷ 6

5. 3,600 ÷ 4 6. 540 ÷ 60

9 6

7 4

900 9


Problem of the Day

Hank wanted to record the number of marbles he lost to his friend Marcus each day for 5 days. He forgot to record one day, but for the other days he wrote 8, 2, 3, and 4. The average number he lost was 4. What number did he forget to write?3


Preview of MA.7.A.3.1 Use and justify the rules for…dividing…integers.

Preview of MA.7.A.3.2 Divide…integers,…including solving problems in everyday contexts.

Sunshine State Standards


Multiplication and division are inverse operations. To solve a division problem, think of the related multiplication.


Additional Example 1: Dividing Integers

Find each quotient.

A. –30 ÷ 6

B. –42 ÷ (–7)

Think: What number times 6 equals –30?

–5 • 6 = –30, so –30 ÷ 6 = –5.

Think: What number times –7 equals –42?

6 • (–7) = –42, so –42 ÷ (–7) = 6.


Check It Out: Example 1

Find each quotient.

A. –15 ÷ 5

B. –36 ÷ (–6)

Think: What number times 5 equals –15?

–3 • 5 = –15, so –15 ÷ 5 = –3.

Think: What number times –6 equals –36?

6 • (–6) = –36, so –36 ÷ (–6) = 6.


Dividing IntegersIf the signs are the same, the product is positive.

24 ÷ 3 = 8 –6 ÷ (–3) = 2

If the signs are different, the quotient is negative.

–20 ÷ 5 = –4 72 ÷ (–8) = –9

Zero divided by any integer equals 0.

= 0 = 0014__ 0

–11 __

You cannot divide any integer by 0.

Because division is the inverse of multiplication, the rules for dividing integers are the same as the rules for multiplying integers.


Additional Example 2A: Evaluating Integer Expressions

Evaluate for each value of d.

d = 16

Write the expression.

= 16 ÷ 4 Substitute 16 for d.

= 4 The signs are the same, so the answer is positive.

d 4__

d 4__

16 4 __


Additional Example 2B: Evaluating Integer Expressions


d = –24


= –24 ÷ 4 Substitute –24 for d.

= –6 The signs are different, so the answer is negative.

d 4__

d 4__

-24 4 ___


Additional Example 2C: Evaluating Integer Expressions


d = –12


= –12 ÷ 4 Substitute –12 for d.


d 4__

d 4__

-12 4 ___


Check It Out: Example 2A

Evaluate for each value of c.

c = –15


= –15 ÷ 3 Substitute –15 for c.


c 3__

c 3__

-15 3 ___


Check It Out: Example 2B


c = 12


= 12 ÷ 3 Substitute 12 for c.

= 4

c 3__

c 3__

12 3 ___

The signs are the same, so the answer is positive.


Check It Out: Example 2C


c = 27


= 27 ÷ 3 Substitute 27 for c.

= 9 The signs are the same, so the answer is positive.

c 3__

c 3__

27 3 __


Standard Lesson Quiz

Lesson Quizzes

Lesson Quiz for Student Response Systems


Lesson QuizFind each quotient.

1. 18 ÷ (–3) 2. –36 ÷ (–6)

3. –64 ÷ (–8) 4. –45 ÷ 3

Evaluate for each value of x.

5. x = –12 6. x = 20

7. Carmen’s mom has $3,200 in her bank

account. If she uses the money to make monthly

rent payments of $375, how many whole

payments can she make?

6–6

8 –15

–3 5

8

x 4__


1. Find the quotient. 32 ÷ (–4)

A. –8

B. –28

C. –26

D. –128



2. Find the quotient. –55 ÷ (–5)

A. 60

B. 11

C. –60

D. –11



3. Evaluate z ÷ 5 for z = –45.

A. –9

B. –40

C. –50

D. –225



4. Stacey has 1,500 grams of flour. She needs 275 grams of flour to bake a cake. How many whole cakes can she bake?

A. 3

B. 4

C. 5

D. 6


Msm1 fl ch11_07

Education

Transcript of Msm1 fl ch11_07