You haven’t given sufficient detail, but if you just want an explanation of what it means then I may be able to help you. Let’s suppose that probability (≥3) in words is “what’s the probability of throwing a die and getting 3 or more?” We would find all possible outcomes (that is, 1, 2, 3, 4, 5, 6) and count how many of these are 3 or more. Yes, there are 4 values. That’s 4 values out of 6 possible: ⁴⁄₆=⅔. So the probability is ⅔.
Get the idea?