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Lesson 5-3: Probability Basics

Scenario: Board Games - Understand probability concepts through dice games and card games!

Duration: 60-75 minutesScenario: Board Games

Learning Objectives

  • Understand what probability means and how to express it
  • Identify possible outcomes and favorable outcomes
  • Calculate simple probabilities using fractions and decimals
  • Apply probability concepts to real-world situations

Dice Game Probability

Rolling a Standard Die

You're playing a board game that uses a standard 6-sided die. You need to understand the probability of different outcomes to make strategic decisions.

Questions:
1. What is the probability of rolling a 3?
2. What is the probability of rolling an even number?
3. What is the probability of rolling a number greater than 4?

1
2
3
4
5
6

Standard 6-sided die faces

Step-by-Step Solutions

Question 1: Probability of rolling a 3

Possible outcomes: 1, 2, 3, 4, 5, 6 (6 total)
Favorable outcomes: 3 (1 total)
Probability = 1/6 ≈ 0.167 or 16.7%

Question 2: Probability of rolling an even number

Possible outcomes: 1, 2, 3, 4, 5, 6 (6 total)
Favorable outcomes: 2, 4, 6 (3 total)
Probability = 3/6 = 1/2 = 0.5 or 50%

Question 3: Probability of rolling a number greater than 4

Possible outcomes: 1, 2, 3, 4, 5, 6 (6 total)
Favorable outcomes: 5, 6 (2 total)
Probability = 2/6 = 1/3 ≈ 0.333 or 33.3%

Probability Concepts

Key Terms

Probability

The likelihood that an event will occur, expressed as a number between 0 and 1.

Formula: P(event) = Favorable outcomes ÷ Total outcomes

Outcomes

All possible results of an experiment or event.

Example: Rolling a die has 6 outcomes: 1, 2, 3, 4, 5, 6

Favorable Outcomes

The specific outcomes that you want to happen.

Example: Rolling an even number: 2, 4, 6

Event

A specific outcome or set of outcomes you're interested in.

Example: "Rolling a 3" or "Rolling an even number"

Probability Scale

Understanding Probability Values

00.250.50.751
Impossible
0%
Unlikely
25%
Even Chance
50%
Likely
75%
Certain
100%

Impossible (0)

Will never happen
Example: Rolling a 7 on a standard die

Certain (1)

Will always happen
Example: Rolling a number 1-6 on a standard die

Practice Problems

Problem 1

A bag contains 3 red marbles, 2 blue marbles, and 5 green marbles. What is the probability of drawing a red marble?

Your solution:

Problem 2

You flip a coin twice. What is the probability of getting heads both times?

Your solution: