static function generates error CS0119:

I have the following code:

 public class Button{ 
    static int Widest;
    static int Height;
    .
    .
    .
    static public void Calc(int c,int w,int ih,int th,int m,int sw,int sh){
       .
       .
       .
    }

 }
 . 
 .
 .
 Button b1 = new Button(tCancel ,can,st);
 Button b2 = new Button(tRestart,res,st);
 Button b3 = new Button(tExit   ,exi,st);
 Button.Calc(3,b1.Wider(b2.Wider(b3)),Font2,Font0,MarginY,Width,Height);   // this line generates an error!

This code generates the following error:

error CS0119: Expression denotes a method group', where a variable', value' or type' was expected

However I don't understand why... If I make Calc non staic like this:

 public void Calc(int c,int w,int ih,int th,int m,int sw,int sh){
       .
       .
       .
    }

and I call it like this:

 b1.Calc(3,b1.Wider(b2.Wider(b3)),Font2,Font0,MarginY,Width,Height); // this compiles OK!

then no error is reported.

Since Calc only affects static varibles inside Button, the logical thing is to make it static, however if I declare it static it simply won't compile... I have lots of static funtions declared, and lots of static function calls either, but this is the only one that gives me trouble... And I can't figure out why.