1) You need to add up the chances that #1 matches #2, or #1 matches #3, or #2 matches #3. The chance of any one of these happening is 1/6. Adding that up, it is 3/6 or 50%. The problem is that within all of these chances there is also the possibility that all three dice will match. Since we only want to count this occurrence once, and we have counted it three times above. So let's subtract 2/18 from the above answer giving 7/18 or 38.9%. I think I got this one wrong.
2) There are two situations here. Either the black dice match or they don't. There is a 1/6 chance that the black dice match. There is further a 1/6 chance that the green die also matches. So 1/6 x 1/6 = 1/36. The second situation is if the black dice do not match. There is a 5/6 chance of this happening. Within this situation, there is a 1/6 chance that the green die matches black die #1 and a 1/6 chance that the green die matches black die #2. You have to add these two, and multiply by 5/6. So you have (1/3) x (5/6) = 5/18. Add this 5/18 to the 1/36 from above and you get 11/36 or 30.6%
3) This one is easy. The first black die can be anything. There is a 1/6 percent chance that the second black die matches, or 16.7%
