Odds express probability as ratio. Odds in favor: favorable outcomes / unfavorable outcomes = p / (1-p). Odds against: unfavorable / favorable = (1-p) / p. Conversion: if odds are a:b, probability = a/(a+b). Key concepts: odds and probability related but different. Common traps: confusing odds with probability, wrong direction (in favor vs against). Exam tips: identify what odds represent, convert to probability if needed. Time-saving: recognize odds notation (a to b or a:b). Example: if probability = 0.4, odds in favor = 0.4/0.6 = 2:3. Betting context: odds 5:1 means 5 to 1, probability = 5/6. Applications: gambling, risk assessment, odds ratios in medical studies. Interpretation: odds 1:1 means equal chance (probability 0.5). Understanding odds essential for risk communication. Practice converting between odds and probability.