0 or 0/36
If the dices have equal probability, that means each number has a 1/6 chance of getting picked because there are 6 sides to a dice with 6 different numbers.
There are a total of 36 combinations, because 6 * 6 is 36.
It would be impossible to have a sum of 1, as the lowest number on both dice is 1. 1 + 1 = 2. Therefore there is a 0/36 probability of getting a sum of 1.