Students love to talk about their birthdays! This activity has students collect classmate birthday data and uses that data to apply to basic probability. This product includes teacher notes, a data recording sheet for students, and 9 questions to relate the data to probability. Questions include: What is the probability of having a birthday on an ODD numbered day? What is the probability of having a birthday during a month containing the letter “Y”? The activity could be used as practice or as a pre/post assessment. No answer key is provided since the data set will be different for each class.