Error: Main method not found in class Vehicle, please define the main method as:
   public static void main(String[] args)
or a JavaFX application class must extend javafx.application.Application

class Vehicle {
    int passengers;
    int mpg;
    int fuelcap;

    void range(){
        System.out.println(mpg*fuelcap);
    }
}

class AddMath {
    public static void main (String args[]) {
        Vehicle minivan = new Vehicle();
        Vehicle sportscar = new Vehicle();

        minivan.passengers = 9;
        minivan.mpg = 12;
        minivan.fuelcap = 14;

        sportscar.fuelcap = 20;
        sportscar.mpg = 24;
        sportscar.passengers = 2;

        minivan.range();

        sportscar.range();
    }
}