It's like a teacher telling a class "Pick a number between 1 and 1000". If they pick the same number as the teacher, they win. If more than one picks the winning number, the first person to get it to the teacher wins.
There's no "many sums to calculate" contributing towards a result. It's more a lottery - did my one calculation produce the right number.
Exactly. For the statisticians in the room, it's a Poisson process. That means that over time your results should average out to meet certain expectations but each individual hash either solves the problem completely or doesn't solve it at all - no in-betweens and no teamwork.
There's no "many sums to calculate" contributing towards a result. It's more a lottery - did my one calculation produce the right number.