Count the number of possible successful outcomes. For example, if you roll one die and you need to roll a three or higher to win, you would count four successful outcomes: 3, 4, 5 or 6. If you want to get heads when you toss a coin, you would have one successful outcome.
Count the number of possible outcomes. A die has six sides, so you have six possible outcomes. A coin has two sides, so you have two possible outcomes.
Divide the number of possible outcomes by the number of total outcomes to find the probability of success. For the die, divide four by six to get 4/6, or about 0.667. For the coin, divide 1 by 2 to get 1/2, or 0.5.
Multiply the probabilities of independent events by each other to find the probability that both events will occur. If you wanted to find the probability of rolling a three or higher and tossing a coin and getting heads, multiply 4/6 by 1/2 to get a 1/3 probability, or about 0.333.