Transcript Course 3 Chapter 2 Lesson 3

1-7 Multiplying and Dividing Integers
Warm Up
Problem of the Day
Lesson Presentation
Lesson Quizzes
1-7 Multiplying and Dividing Integers
Warm Up
Multiply or divide.
1. 5(8)
3.
36
9
5. 18(7)
40
4
126
2. 6(12)
4.
6.
49
7
192
16
72
7
12
1-7 Multiplying and Dividing Integers
Problem of the Day
Complete the pyramid by filling in the
missing numbers. Each number is the
sum of the numbers in the two boxes
below it.
–4
–8
–7
2
–9
4
–1
5
8
–3
1-7 Multiplying and Dividing Integers
Learn to multiply and divide integers.
1-7 Multiplying and Dividing Integers
A positive number multiplied by an integer can be
written as repeated addition.
3(–200) = –200 + (–200) + (–200) = –600
From what you know about adding and subtracting
integers, you can see that a positive integer times
a negative integer is negative.
1-7 Multiplying and Dividing Integers
You know that
multiplying two
positive integers
together gives you
a positive answer.
Look for a pattern
in the integer
multiplication at
right to
understand the
rules for
multiplying two
negative integers.
3(–200) = –600
2(–200) = –400
1(–200) = –200
0(–200) = 0
+ 200
+ 200
+ 200
–1(–200) = 200 The product of
two negative
–2(–200) = 400 integers is a
positive
–3(–200) = 600
integer.
1-7 Multiplying and Dividing Integers
1-7 Multiplying and Dividing Integers
Additional Example 1: Multiplying and Dividing
Integers
Multiply or divide.
A. –6(4)
Signs are different.
–24
Answer is negative.
B. –8(–5)
Signs are the same.
Answer is positive.
40
1-7 Multiplying and Dividing Integers
Additional Example 1: Multiplying and Dividing
Integers
Multiply or divide.
C.
–18
2
–9
D.
Signs are different.
Answer is negative.
–25
–5
Signs are the same.
5
Answer is positive.
1-7 Multiplying and Dividing Integers
Check It Out: Example 1
Multiply or divide.
A. 5(–2)
Signs are different.
–10
Answer is negative.
B. –3(–2)
Signs are the same.
Answer is positive.
6
1-7 Multiplying and Dividing Integers
Check It Out: Example 1
Multiply or divide.
C.
–24
3
–8
D.
Signs are different.
Answer is negative.
–12
–2
Signs are the same.
6
Answer is positive.
1-7 Multiplying and Dividing Integers
Additional Example 2: Using the Order of Operations
with Integers
Simplify.
A. 3(–6 – 12)
Subtract inside the parentheses.
3(–18)
Think: The signs are different.
–54
The answer is negative.
B. –5(–5 + 2)
Subtract inside the parentheses.
–5(–3)
Think: The signs are the same.
15
The answer is positive.
1-7 Multiplying and Dividing Integers
Additional Example 2: Using the Order of Operations
with Integers
Simplify.
C. –2(14 – 5)
Subtract inside the parentheses.
–2(9)
Think: The signs are different.
–18
The answer is negative.
1-7 Multiplying and Dividing Integers
Check It Out: Example 2
Simplify.
A. 2(1 – 8)
Subtract inside the parentheses.
2(–7)
Think: The signs are different.
–14
The answer is negative.
B. 4(–3 – 8)
Subtract inside the parentheses.
4(–11)
Think: The signs are different.
–44
The answer is negative.
1-7 Multiplying and Dividing Integers
Check It Out: Example 2
Simplify.
C. –3(6 – 9)
Subtract inside the parentheses.
–3(–3)
Think: The signs are the same.
9
The answer is positive.
1-7 Multiplying and Dividing Integers
Additional Example 3: Sports Application
A golfer plays 5 holes. On 3 holes, he is 4
strokes over par. On 2 holes, he is 1 stroke
under par. Each score over par can be
represented by a positive integer, and each
score under par can be represented by a
negative integer. Find the total score relative
to par.
3(4) + 2(–1)
Add the losses to the gains.
12 + (–2)
Multiply.
10
Add.
The total score is 10 strokes over par.
1-7 Multiplying and Dividing Integers
Check It Out: Example 3
A golfer plays 9 holes. On 3 holes, he is 3
strokes over par. On 4 holes, he is 3 stroke
under par. Each score over par can be
represented by a positive integer, and each
score under par can be represented by a
negative integer. Find the total score relative
to par.
3(3) + 4(–3)
Add the losses to the gains.
9 + (–12)
Multiply.
–3
Add.
The total score is 3 strokes under par.
1-7 Multiplying and Dividing Integers
Lesson Quizzes
Standard Lesson Quiz
Lesson Quiz for Student Response Systems
1-7 Multiplying and Dividing Integers
Lesson Quiz
Multiply or divide.
1. –8(4) –32
2. –12(5)
–10
6
Simplify.
3. –2(13 – 4) –18
4. 6(–5 – 3) –48
5. Evin completes 11 transactions in his bank
account. In 6 transactions, he withdraws
$10. In 5 transactions, he deposits $20.
Find the total net change in dollars.
$40
1-7 Multiplying and Dividing Integers
Lesson Quiz for Student Response Systems
1. Multiply –9(6).
A. 54
B. 45
C. –45
D. –54
1-7 Multiplying and Dividing Integers
Lesson Quiz for Student Response Systems
–19(4)
2. Multiply or divide
.
–4
A. –19
B. 19
C. 30
D. 36
1-7 Multiplying and Dividing Integers
Lesson Quiz for Student Response Systems
3. Simplify –7(17 – 6).
A. –77
B. –66
C. 66
D. 77
1-7 Multiplying and Dividing Integers
Lesson Quiz for Student Response Systems
4. Simplify 9(–6 – 1).
A. 63
B. 54
C. –63
D. –64
1-7 Multiplying and Dividing Integers
Lesson Quiz for Student Response Systems
5. Hannah makes 14 trips to her mom’s home.
On 8 of her trips, she gives her mom $25
for safekeeping. On her other 6 trips, she
takes $30 from her mom. How much of
Hannah’s money is left with her mom?
A. $10
B. $20
C. $30
D. $40