A die will be rolled three times, true or false: the chance of getting at least one ace is 1/2

True. It's an OR because you said at least one out of three rolls. It's the same as rolling three six-sided dice and asking the chances of at least one of them being an ace. Each chance is 1/6, but you get 3 chances.

Edit... an OR condition is usually an addition; i.e. 1/6 + 1/6 + 1/6 = 3//6 = 1/2 = 50%

False.

6 sides to the die gives you a 1:6 chance of getting your desired roll.

The number of times you roll does not increase your chances, because each time has the same 1:6 chance.