The probability of not throwing a 1 in two die throws is 5^2 / 6^2 = 25/36 = 69.4%. So the odds of throwing a 1 are just the reverse, 36/36 - 25/36 = 11/36 or 30.6%. The formula scales nicely out to the Xth toss for example the probability of not throwing a 1 in ten die throws is 5^10 / 6^10 = 9765625/60466176 = 16.1%.
But instead of figuring out the probability of something NOT happening and doing subtraction, can the formula be written purely from the positive perspective? Such that, "What's the probability of rolling a one in X throws of a die?"