Probability is the chance or likelihood that an event will happen. It is the ratio of the number of ways an event can occur to the number of possible outcomes. We'll use the following model to help calculate the probability of simple events.
As you can see, with this formula, we will write the probability of an event as a fraction. The numerator (in red) is the number of chances and the denominator (in blue) is the set of all possible outcomes. This is also known as the sample space.
Let's take a look at a few examples of probability.
Now let's take a look at a probability situation that involves marbles.
Hopefully these two examples have helped you to apply the formula in order to calculate the probability for any simple event.
Now, it's your turn to try! Check out the spinner in the practice problem below.
Great Job! You've got the basics, now you are ready to move on.
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