Develop a multithreaded application in C# that creates 4 separate threads. Associate each thread to one distinct method. Each method should contain time-consuming calculations (if you wish, you may use for loops to, to make the execution time even longer.) You may wish to get the input from the user and pass them to the 4 methods that would run in 4 threads you created. The idea is to let all the methods run concurrently. Please make sure that your methods do some useful calculations based on the input entered by the users. Use your creativity for this matter.

Note:I want 4 methods that runs in 4 threads.