1. Section 1.9 Multiplying and Dividing Integers
Algebra Concepts
Section 1.9
Multiplying and Dividing Integers

2. Warmup Decide if the following are addition or subtraction
problems and find the answer.
#1 −6+2
#2 −9− −2
#3 8−10
#4 −20+(−3)

3. Multiplication is repeated addition.
−6+ −6 + −6 + −6 + −6
Is the same as
−6 5
Answer −30

4. When multiplying integers, always multiply.
The sign of the product depends on the signs of the factors.
When multiplying two integers,
Same signs→ + (positive answer)
Different signs→ − (negative answer)

5. Multiply
#1 −4 −5 #2 6 −3 #3 −1 −1 #4 −5 −2 10 #5 2 6 #6 (8)(0)

6. When dividing integers, always divide.
The sign of the quotient depends on the signs of the numbers being divided.
When dividing two integers,
Same signs→ + (positive answer)
Different signs→ − (negative answer)

7. # ÷ −5
#2 30÷ −3
#3 −18 ÷ −2
#4 −8 ÷2
#5 0÷ −5
#6 60÷10

8. What does average mean?

9. Finding an average (also called the mean) gives you a single number to describe a group of numbers.

10. To find an average #1 find the total (sum) of the numbers you’re averaging #2 divide by the quantity of numbers you’re

11. Find the average
#1 Katie spent $4, $6 $5.50, $2,50 and $4 on her lunches last week. Find the average amount she spent per day. #2 Johnny ran three miles for three days and ran that distance in 24, 27 and 21 minutes, respectfully. Find the average time it took him to run three miles for the three days.

12. Decide what operation is used to simplify and then simplify.
#1 4− −2 #2 −4 2 #3 −3 + −6 #4 −12 −4 #5 9÷(−3)