well .. you have String values of your input in your String args. so, considering you calling methods in the same class as your main method, I would assume you have two possible solutions:
1. you create a couple of static class variables, in which you store the values you get from your command line args. Since these would be class variables, they would be accessible in your static methods. 2. you pass your variables as parameters to your methods, so they will automatically be accessible in these methods. I would suggest to take this approach.
Pass the String args as a parameter to the method, and parse it as int or double if needed. Alternatively, you could parse it as int or double if needed and then pass the result to the method. The latter is nice because it allows you to detect bad input early on and just bug out with an error message.
Unfortunately, there's no way to test whether a String can be parsed as a number without trying it, so you're going to generate an exception on bad input. This is a reasonable way to handle that.
Now I don't know what happens after this, but you'll probably want to include some logic to continue correctly depending on whether the input was good and the method called or not - this is left as an exercise. :)