Probability is a numerical measure of how likely an event is to happen. Probability is measured in fractions between 0 and 1. (0 is impossible; 1 is certain.) Sometimes, probability is represented as a percentage -- from 0 percent to 100 percent.
In probability, we talk about events" and outcomes." An event is anything that happens. An outcome is the result of what happens. A coin flip, for example, can have two possible results -- heads or tails. When you flip a coin (an event), the result (outcome) is either heads or tails.
Probability tells you which outcome -- heads or tails -- is more likely to occur in any given event. You can determine the probability of a particular outcome by dividing the number of times that the outcome has occurred by the total number of events. To find the probability that a flipped coin will come up heads, for example, you might flip the coin 25 times. If the coin turns up heads 10 times, then the probability that the coin will land heads up on the next flip is 10/25, or 2/5.
Probability Interactive Activities