This self checking worksheet has 10 word problems that gives the students the probability of something happening, and they must find the probability that it happens at least once. Example: If four children open their new box of eight crayons and randomly selects one, what is the probability that at least one child selects the red crayon first? The solution is 1 - P(no child selects red) = 1 - (7/8)^4 = 0.414. My students had trouble with this concept, so I made them a worksheet with more problems that the book offered. Although one of my students said the question above was wrong, because every child actively seeks the red crayon first. Ha!!
When finished with this worksheet, the students reveal a solution to a riddle.