Please see below.
Can also just say to whoever is helping me out, you are pretty much awesome, and I will try and help others out as much as I can on this forum!
Found the answer to this by the way, here it is if your intersted
Discrete distribution taking only non-negative integer values
When a random variable takes only values in {0,1,2,3,...} we can use the following formula for computing its expectation:
Proof:
interchanging the order of summation, we have