1. Warm Up
Problem of the Day
Lesson Presentation
Lesson Quizzes

2. Warm Up
Decide whether each event is independent or dependent. Explain your answer.
1. Bill picks a king from a pile of cards and keeps it. On his next turn he tries for a queen.
2. the chance of it raining on the third Tuesday of the month after it has rained on the first Tuesday
Dependent; there are fewer cards from which to choose.
Independent; the rain on the first Tuesday has no effect on the weather two weeks later.

3. Problem of the Day
There are 7 players. Can more teams of 2 different people or 5 different people be formed? (Hint: Look for a shortcut.)‏
The same number of both can be formed. For every 5-person team there is a 2-person team (the 2 players left out).

4. Learn to find the number of possible combinations.

5. Vocabulary
combination

6. Mrs. Logan’s class has to read any two of the following books.
1. The Adventures of Tom Sawyer, by Mark Twain
2. The Call of the Wild, by Jack London
3. A Christmas Carol, by Charles Dickens
4. Treasure Island, by Robert Louis Stevenson
5. Tuck Everlasting, by Natalie Babbit
How many possible combinations of books could the students choose?

7. A combination is a grouping of objects or events in which the order does not matter. For example, a student can choose books 1 and 2 or books 2 and 1. Since the order does not matter, the two arrangements represent the same combination. One way to find possible combinations is to make a table.

8. Additional Example 1: Using a Table to Find Combinations
Kristy’s Diner offers customers a choice of 4 side
dishes with each order: carrots, corn, french fries, and mashed potatoes. How many different combinations of 3 side dishes can Kareem choose?
Begin by making a table showing all the possible choices of side dishes taken three at a time.
4, 2, 3
3, 2, 4
2, 3, 4
1, 3, 4
4, 1, 3
3, 1, 4
2, 1, 4
1, 2, 4
4, 1, 2
3, 1, 2
2, 1, 3
1, 2, 3

9. Additional Example 1 Continued
Because order does not matter, you can eliminate repeated triples. For example 1, 2, 3 is already listed, so 2, 1, 3 can be eliminated.
4, 2, 3
3, 2, 4
2, 3, 4
1, 3, 4
4, 1, 3
3, 1, 4
2, 1, 4
1, 2, 4
4, 1, 2
3, 1, 2
2, 1, 3
1, 2, 3
There are 4 possible combinations of 3 side dishes
Kareem can choose with his order.

10. y, g, b b, g, y g, b, y r, b, y y, r, b b, r, y g, r, y r, g, y
Check It Out: Example 1
Jim is packing for a trip. He has 4 different colors of shirts: red, green, blue, and yellow
(r, g, b, y). He only has room for 3 of them.
How many different combinations of 3 shirts can Jim choose for his trip?
Begin by making a table of all the possible choices of shirts taken three at a time.
y, g, b
b, g, y
g, b, y
r, b, y
y, r, b
b, r, y
g, r, y
r, g, y
y, r, g
b, r, g
g, r, b
r, g, b

11. Check It Out: Example 1 Continued
Because order does not matter, you can eliminate repeated triples. For example r, g, b is already listed so g, r, b can be eliminated.
y, g, b
b, g, y
g, b, y
r, b, y
y, r, b
b, r, y
g, r, y
r, g, y
y, r, g
b, r, g
g, r, b
r, g, b
There are 4 possible combinations of 3 shirts
that Jim can choose to bring on his trip.

12. Understand the Problem
Additional Example 2: Problem Solving Application
Lara is going to make a double-dip cone from a choice of vanilla, chocolate, and strawberry. She wants each dip to be a different flavor. How many different cone combinations can she choose from? 1
Understand the Problem
Rewrite the question as a statement.
• Find the number of possible combinations of two flavors Lara can choose.
List the important information:
• There are three flavor choices in all.

13. Additional Example 2 Continued
Make a Plan
You can make a tree diagram to show the
possible combinations.

14. Additional Example 2 Continued
Solve 3
Strawberry
Vanilla
Vanilla
Chocolate
Chocolate
Strawberry
Chocolate
Strawberry
Vanilla
The tree diagram shows 6 possible ways to combine two flavors, but each combination is listed twice. So
there are 6 ÷ 2 = 3 possible combinations.

15. Additional Example 2 Continued4
Look Back
You can also check by making a table. The vanilla
can be paired with two other flavors and the
chocolate with one. The total number of possible
pairs is = 3.

16. Understand the Problem
Check It Out: Example 2
Hamilton had three types of cookies: sugar, chocolate chip, and oatmeal. He wants to put them into packages, with each package containing two different flavors of cookies. How many different packages can he make? 1
Understand the Problem
Rewrite the question as a statement.
• Find the number of possible combinations that
Hamilton can choose.
List the important information:
• There are three cookie types in all.

17. Check It Out: Example 2 Continued
Make a Plan
You can make a tree diagram to show the
possible combinations.

18. Check It Out: Example 2 Continued
Solve 3
Sugar
Chocolate chip
Sugar
Oatmeal
Chocolate chip
Oatmeal
Oatmeal
Chocolate chip
Sugar
The tree diagram shows 6 possible ways to combine
two types, but each combination is listed twice. So
there are 6 ÷ 2 = 3 possible combinations.

19. Check It Out: Example 2 Continued4
Look Back
You can also check by making a table. The oatmeal
can be combined with two other types and the
chocolate chip with one. The total number of possible
pairs is = 3.

20. Lesson Quiz for Student Response Systems
Lesson Quizzes
Standard Lesson Quiz
Lesson Quiz for Student Response Systems 20 20 20 20

21. Lesson Quiz
1. A pizzeria has on special a pizza with 2 toppings for $9.95. It offers pepperoni, olives, tomato, sausage, bacon, mushrooms, and ham as toppings. How many different specials could you build?
2. Jaime has a red shirt and a blue shirt. She has a green scarf, a yellow scarf, and a purple scarf. How many different shirt-scarf combinations can she wear?
3. Karl has to pick two reptiles to write a report on. If there are 8 possible reptiles to choose from, how many pairs are possible? 21 6 28

22. Lesson Quiz for Student Response Systems
1. An ice cream parlor offers a discount on a triple sundae that is made of 3 flavors. You can choose from chocolate, vanilla, strawberry, mint, and butterscotch. How many different combinations are possible?
A. 5
B. 6
C. 8
D. 10 22 22 22 22

23. Lesson Quiz for Student Response Systems
2. On the opening day, a restaurant offers free drinks and desserts to all the customers. A customer can choose from apple juice, orange juice, grape juice, and cranberry juice. He can choose from ice cream, cake, and pudding as desserts. How many different juice-dessert combinations are possible?
A. 7
B. 12
C. 15
D. 24 23 23 23 23

24. Lesson Quiz for Student Response Systems
3. How many 2-letter combinations are possible from the letters in the word MATH?
A. 2
B. 4
C. 6
D. 8 24 24 24 24