Probability
Calculate probability in Grade 6 math by writing favorable outcomes over total possible outcomes — express likelihood as a fraction, decimal, or percent and interpret results.
Key Concepts
Property Probability is a number from 0 to 1 that measures the likelihood of an event. An event that is certain to occur has a probability of 1. An event that is certain not to occur has a probability of 0.
Examples $P(\text{rolling a 7 on a 6 sided die}) = 0$ $P(\text{rolling a number less than 7 on a 6 sided die}) = 1$ $P(\text{flipping a coin and getting tails}) = \frac{1}{2}$.
Explanation Think of probability as a 'likeliness meter' for uncertain events. Is it definitely going to snow tomorrow (a probability of 1)? No way (a probability of 0)? Or is it a maybe, like a 50/50 coin flip? The closer the number is to 1, the more likely something is to happen. It's the mathematical way of saying 'probably'!
Common Questions
How do you write the probability of an event?
Probability equals the number of favorable outcomes divided by the total number of possible outcomes. Write it as a fraction, then convert to a decimal or percent if needed. For example, rolling a 3 on a six-sided die is 1 out of 6.
What does a probability of 0 or 1 mean?
A probability of 0 means the event is impossible and will never happen. A probability of 1 means the event is certain and will always happen. All probabilities fall between 0 and 1 inclusive.
How is probability different from possibility?
Possibility is whether something can happen at all, a yes or no answer. Probability measures how likely it is to happen using a number from 0 to 1. An event can be possible but still have very low probability.
What common mistakes do students make with probability?
Students often list outcomes incorrectly or forget that all outcomes must be equally likely. Also, probability greater than 1 is impossible — always check that your favorable outcomes do not exceed the total outcomes.