M&M counter program

import java.util.Scanner;
//This is a program I wrote to predict the number of M&Ms in a bag based on previous bags.
public class MandMPredictor {
//This is the first program I've written solely by myself. Please comment tips!
    public static void main(String[] args) {
        Scanner keyboard = new Scanner(System.in);
        int  numRed, numBlue, numOrange, numGreen, numBrown, numYellow, totalPrevious, previousBags, previousAdd, finalAdd, finalSubtract;

        System.out.println("Welcome, one and all, to the great M&M's calculator!");
        System.out.println("Please Enter the total number of bags opened beforehand.");
        previousBags = keyboard.nextInt(); //Samrg472: Input 0 as the number for previousBags. Watch the system crash XD
        System.out.print("So thats ");
        System.out.print(previousBags);
        System.out.println(" Bags beforehand? Ok, onto the next part.");

        System.out.println("How many M&Ms were in the bags? This should be COMBINED, not an average.");
        totalPrevious = keyboard.nextInt();
        System.out.println("Got it! So, there were " + totalPrevious + " M&M's in the previous bags? Ok then! next!");

        System.out.println("How many RED M&Ms were there? Again, this should be the total combined, not the average.");
        numRed = keyboard.nextInt();
        System.out.println("How many BLUE M&Ms were there?");
        numBlue = keyboard.nextInt();
        System.out.println("How many ORANGE M&Ms were there?");
        numOrange = keyboard.nextInt();
        System.out.println("How many GREEN M&Ms were there?");
        numGreen = keyboard.nextInt();
        System.out.println("How many BROWN M&Ms were there?");
        numBrown = keyboard.nextInt();
        System.out.println("Last one! How many YELLOW M&M's were there?");
        numYellow = keyboard.nextInt();
        System.out.println("Thank you for the inputs. Beginning processing...");
        numRed = (numRed / previousBags) - 2;
        numBlue = (numBlue / previousBags) - 2;
        numOrange = (numOrange / previousBags) - 2;
        numGreen = (numGreen / previousBags) - 2;
        numBrown = (numBrown / previousBags) - 2;
        numYellow = (numYellow / previousBags) - 2;
        finalAdd = numYellow + numBrown + numGreen + numOrange + numBlue + numRed;
        finalSubtract = (totalPrevious / previousBags) - finalAdd;
        finalAdd = finalAdd + finalSubtract;
        System.out.println("OK! Calculations complete!");
        System.out.println("This machine estimates that there are " + numRed + " Red, " + numBlue + " Blue, " numOrange + " Orange, " + numGreen + " Green, " + numBrown + " Brown, and " + numYellow + "Yellows. There are also" + finalSubtrackt + " Unknown. These are the ones that I cannot calculate precisely." );
        System.out.println();
        System.out.println("All in all, there are " + finalAdd + "M&Ms total.);
        System.out.println("Thank you for using the M&M Predictatron. Code by Matthew Weidenhamer.");
    }
}