Define the sample space
Identify the event of interest
Count favorable outcomes
Count total possible outcomes
Compute probability as favorable outcomes divided by total outcomes
Simplify the fraction if possible
Express the result as a fraction, decimal, or percentage
For independent events, multiply their probabilities
For dependent events, adjust the probability after each outcome
For mutually exclusive events, add their probabilities
Use the complement rule when it is easier
Check that the probability is between 0 and 1