6 is right. 7, the fraction is right, but the equation doesn't make sense. It would be .25, not 2.5.
I'll work through 8 with you, and it should help with the rest. Okay, so you have 6 possible outcomes: 1, 2, 3, 4, 5, and 6. The question is "What's the probably of not getting a 5?" Well, the probability of getting a 5 is 1/6, so not getting a 5 would be 5/6 or about 83.3%