Another way to look at it.
If the odds of rolling {2,3,4...12} are the same then the average is the sum of these numbers / 11.
The sum series from I=0 to 10 of (I+2) is computed.
To solve this, take out the 2. Because it's repeated 11 times, then 2*11+ sum from I=0 to 10 of I remains.
Sum series solution is ((10+1)*10)/2.
So 22+(10+1)*(10/2)= 22+55=77.
Find the average by dividing by 11. 77/11=7
