Threading.Tasks.Task' does not contain a definition for 'Result'

You're returning Task from the CreatingTask method - you need to return Task<int>, and then change tasks to be Task<int>[] instead of Task[].

Basically, Task represents a task which doesn't produce a result - whereas Task<T> represents a task producing a result of type T. In your case, everything throughout your code returns int, so you need Task<int> everywhere.

You will get this error if you're trying to use .Result on a Task object. This might be because you meant to use Task<T>. But, if you want meant to use Task and you want it to return without using await then Task is like void and does not have a result. You can use .Wait() instead. This returns void.