1. Lesson 2.4 – 2.5 Multiplying and Dividing Integers
Essential Question: How do you multiply and divide integers?

2. Before we start…
Suppose the water level in the pool is decreasing 2 inches each hour. What is the change in water level after 7 hours?

3. How do you multiply and divide integers?
Same Signs The product and quotient of two integers with the same sign is positive.
Different Signs The product and quotient of two integers with different signs is negative.

4. −5 −7 −8 2
−12 0 −3 −4

5. −9 2 5 −5
0 −14 −8 −3

6. 28÷ −4 −60 −12
0÷−13 64÷ −8

7. −72 −18 0÷ −3
10÷2 15 −3

8. −81÷ −9 3 −7
− −7

9. Multiplication Properties
Multiplication Property of Zero
Words The product of a number and 0 and 0.
Numbers −6∙0=0
Algebra 𝑎∙0=0
Identity Property of Multiplication
Words The product of a number and the multiplicative identity is the number.
Numbers 5∙1=5
Algebra 𝑎∙1=𝑎

10. Evaluate 𝑎 2 when 𝑎=−3 Evaluate 𝑥𝑦𝑧 when 𝑥=2, 𝑦=−4, 𝑧=6

11. Evaluate −2𝑎𝑏 when 𝑎=−3, 𝑏=5 Evaluate 𝑥 2 𝑦 when 𝑥=−2, 𝑦=3

12. How do you calculate the mean?
The mean is the average of the data. To calculate the mean: - Add up the data - Divide by the number of data in the set

13. Cold Temperatures The table shows the high temperatures for five days in January in Bangor, Maine. What is the average daily high temperature?
Day
Temperature
Monday
3°C
Tuesday
-3°C
Wednesday
-5°C
Thursday
2°C
Friday
-7°C

14. Bowling Alley A bowling alley’s gains and losses over 5 months are $450, -$675, $1230, -$776, and -$95. Find the mean of the monthly gains and losses for the bowling alley.

15. Golf Find the mean of the following golf scores for 9 holes of golf, expressed as strokes above or below par: 0, 5, −1, 1, 0, −3, 0, −2, 4.

16. Greenland Most of Greenland is covered with ice that is almost two miles thick in some places. Scientists estimate that 3 feet of this ice melts each year. Find the change in thickness of the ice after 10 years.

17. Weight Loss Jared lost 4 pounds per month for 8 months
Weight Loss Jared lost 4 pounds per month for 8 months. What is his change in weight?

18. How do you multiply and divide integers?

19. Ticket Out the Door
−5 4 −2 10