Probability and Chance
Probability measures how likely an event is to occur, expressed as a fraction, decimal, or percentage between 0 (impossible) and 1 (certain). In Grade 6 Saxon Math Course 1 (Chapter 6: Geometry and Number Operations), students use the formula P(event) = favorable outcomes ÷ total possible outcomes. Rolling a 3 on a standard die has probability 1/6, since there is 1 favorable outcome out of 6 equally likely outcomes. Students distinguish theoretical probability (mathematically calculated) from experimental probability (observed from actual trials), and learn that more trials bring experimental results closer to theoretical predictions.
Key Concepts
New Concept Probability is the measure of how likely an event is to happen. It is expressed as a number between 0 (impossible) and 1 (certain).
If all outcomes of an experiment or game have the same probability, then the probability of an event is: What’s next This is just the foundation. Soon, you'll apply this formula to worked examples involving spinners, number cubes, and complementary events to master this concept.
Common Questions
What is the formula for probability in Grade 6?
P(event) = number of favorable outcomes ÷ total number of possible outcomes. The result is always a number between 0 and 1.
What is the probability of flipping heads on a fair coin?
1/2 or 0.5, because there is 1 favorable outcome (heads) out of 2 equally likely outcomes (heads or tails).
What is the difference between theoretical and experimental probability?
Theoretical probability is calculated mathematically before any experiment. Experimental probability is calculated from actual trial results. More trials make experimental probability approach the theoretical value.
How do you express probability as a percent?
Divide favorable outcomes by total outcomes, then multiply by 100. A probability of 1/4 equals 0.25, which is 25%.
A bag has 3 red and 5 blue marbles. What is the probability of picking red?
P(red) = 3 ÷ (3+5) = 3/8 = 0.375 = 37.5%.
What does a probability of 0 or 1 mean?
Probability 0 means the event is impossible. Probability 1 means the event is certain to happen.