Welcome to probability! Probability is a mathematical way to measure how likely an event is to happen. The basic formula is the number of favorable outcomes divided by the total number of possible outcomes. Probability always ranges from zero to one, where zero means impossible and one means certain. For example, when flipping a fair coin, the probability of getting heads is one out of two, or zero point five.
Let's break down the probability calculation into four simple steps. First, identify the specific event you're interested in. Second, count how many favorable outcomes there are. Third, count the total number of possible outcomes. Fourth, apply the formula by dividing favorable by total. For example, when rolling a dice and wanting to get a three, there's one favorable outcome out of six total possibilities, giving us a probability of one-sixth or about zero point one six seven.
Let's work through a classic example: drawing a red card from a standard deck. First, we identify our event as drawing a red card. Second, we count the favorable outcomes, which is twenty-six red cards consisting of thirteen hearts and thirteen diamonds. Third, the total possible outcomes is fifty-two, the total number of cards in the deck. Finally, we calculate twenty-six divided by fifty-two, which simplifies to one-half or fifty percent.
Let's look at two more examples to reinforce our understanding. First, rolling an even number on a dice. The favorable outcomes are two, four, and six, giving us three favorable outcomes out of six total. This gives us a probability of three-sixths or one-half. Second, drawing an Ace from a deck. There are four Aces in a standard fifty-two card deck, so the probability is four over fifty-two, which simplifies to one-thirteenth or about zero point zero seven seven.
To summarize what we've learned about calculating probability: Probability is a way to measure how likely events are to happen. Always use the basic formula of favorable outcomes divided by total outcomes. Remember that probability ranges from zero to one. Follow the four-step process we discussed, and practice with different examples to build your understanding and confidence.