Lesson 2.5, For use with pages 77-81

Find the quotient.

1. 21 ÷ 3 2. 48 ÷ 8 3. 52 ÷ 13

Lesson 2.5, For use with pages 77-81

ANSWER 6ANSWER 7

Find the quotient.

ANSWER 4

1. 21 ÷ 3 2. 48 ÷ 8 3. 52 ÷ 13

Dividing IntegersDay 1

Lesson 2.5

Pages 77-81

Division Rules• a POSITIVE divided by POSITIVE is POSITIVE

(+) ÷ (+) = (+)

• a NEGATIVE divided by NEGATIVE is POSITIVE(-) ÷ (-) = (+)

• a POSITIVE divided by NEGATIVE is NEGATIVE(+) ÷ (-) = (-)

• a NEGATIVE divided by POSITIVE is NEGATIVE(-) ÷ (+) = (-)

EXAMPLE 1

Same sign, so quotient is positive.

= –7 Different signs, so quotient is negative.

c. 36–9 = –4 Different signs, so quotient is negative.

= 0d. 0–7

a. – 40–8

b. –142

Dividend is 0 so quotient is 0.

Dividing Integers

= 5

Practice: • Perform the indicated operation.

1.21 ÷ -7 =

2.35 ÷ 5 =

3.-90 ÷ 15 =

4.64 ÷ -16 =

5. -88 ÷ 11 =

6. -221 ÷ -13 =

7. I-81I ÷ I9I =

8. -10 ÷ 0 =

Practice: • Perform the indicated operation.

1.21 ÷ -7 =

2.35 ÷ 5 =

3.-90 ÷ 15 =

4.64 ÷ -16 =

97

-6

-4

-8

17-3

Undefined

5. -88 ÷ 11 =

6. -221 ÷ -13 =

7. I-81I ÷ I9I =

8. -10 ÷ 0 =

EXAMPLE 2 Finding a Mean

One of the coldest places on Earth is the Russian town of Verkhoyansk, located near the Arctic Circle. Find the mean of the average high temperatures during winter in Verkhoyansk. Use the data in the table.

Temperatures

EXAMPLE 2

SOLUTION

STEP 1 Find the sum of the temperatures.

–41 + (–40 ) + (–48 ) + (–18 )

STEP 2 Divide the sum by the number of temperatures.

–1474

ANSWER The mean of the temperatures is about -37oF.

Finding a Mean

= –147

= –36.75

GUIDED PRACTICE for Examples 2 and 3

Find the mean of the data.

1. –16, 17, 8, –23, –31

SOLUTION

STEP 1 Find the sum of the values.

–16 + 17 + 8 + (–23) + (–31)

STEP 2 Divide the sum by the number of values.

–455

ANSWER The mean of the data is about –9.

= –45

= –9

GUIDED PRACTICE for Examples 2 and 3

Find the mean of the data.

2. 0, –4, –10, 4, 11, –9, –13

SOLUTION

STEP 1 Find the sum of the values.

0 + (–4) + (–10) + 4 + 11 + (–9) + (–13)

STEP 2 Divide the sum by the number of values.

–217

ANSWER The mean of the data is about –3.

= –3

= –21

Find the mean of the data.

Homework

• Page 79 #1-17, 38-41– Problems 12-13 will have one number after

the decimal.– Problems 16-17 will have decimals in their

answers. Round to the nearest hundredths (two numbers after the decimal).