It is 20/1296 = 0.01543 (approx).
The probability of getting a sum of 2 at least once is 0.8155
The probability is 26/36 = 13/18.
33,33333...%
The probability of getting an odd number when you roll one die is 1 in 2. In order to get an odd sum with two dice, one of them has to be odd and one of them has to be even. The probability of rolling an odd sum is still 1 in 2, since each die is unrelated in probability to the other.
5/12
For a single roll of a pair of fair dice, the answer is 1/36.
The experiment is undefined. On a single roll of eight or more normal dice the probability of getting a sum of 7 is 0.
The probability is certain or 1. The max you can roll is 12 so it is certain the sum will be less than 13.
6:5
50%
The probability of rolling a sum of 12 in a single roll of two dice is 1 in 36, or about 0.0278.
The probability is 0 since if both dice show the number 6, their sum is 12 which is not a prime.