Not static example

App.java

/*



    3. Program stores student response in a double precision floating-point variable

    4. Program uses floating-point comparison to determine if the students answer is correct

    9. Program shall display the number of correct and incorrect responses at the end of a session

    17. choose 5 is a mix of addition, subtraction, multiplication, and division.)
*/

import java.security.SecureRandom;
import java.util.Random;
import java.util.Scanner;

public class App
{
	private int level;

	private App()
	{
		Scanner scan = new Scanner(System.in);
		int probType;
		int level;

		System.out.println(" Welcome to Computer-Assisted Instruction (CAI)");
		do
		{

			System.out.println(
					"| 1 = 1 digit\n| 2 = 2 digit\n| 3 = 3 digit\n| 4 = 4 digit");
			System.out.print(" Choose difficulty  Level 1 - 4: ");

			level = scan.nextInt();
			if(level >= 5 || level <= 0)
			{
				System.out.println("Error number: " + level
						+ ", Levels are from 1 to 4, Try again!\n");
			}

		}
		while(level >= 5 || level <= 0);
		do
		{
			System.out
					.print("| 1 = Addition \n| 2 = Subtraction \n| 3 = Multiplication \n| 4 = Division \n"
							+ "| 5  = Random Type \n"
							+ "| Choose Problem Type: ");
			probType = scan.nextInt();
			if(probType >= 6 || probType <= 0)
			{
				System.out.println("Error number: " + probType
						+ ", problem Type are from 1 to 5, Try again!\n");
			}

		}
		while(probType >= 6 || probType <= 0);

		System.out
				.print("______________________________________________________________________\n");
		String ant = problemType(probType);

		startApp(level, ant, scan);
	}

	private void startApp(int level, String maths, Scanner scan)
	{
		this.level = level;

		int x1;
		int x2;
		int reset;
		int answer;
		int correctAns = 0;
		int grade = 0;

		do
		{

			for(int i = 0; i < 10; ++i)
			{
				String proType = ":)";
				x1 = genRNum();
				x2 = genRNum();

				switch(maths)
				{
					case "Random":
						int x3 = getRanNum(3);
						System.out.println(x3);
						switch(x3)
						{
							case 0:
								proType = "+";
								correctAns = (x1 + x2);
								break;
							case 1:
								proType = "-";
								correctAns = (x1 - x2);
								break;
							case 2:
								proType = "*";
								correctAns = (x1 * x2);
								break;
							case 3:
								proType = "/";
								if(x2 < 1 || x1 != x2)
								{
									correctAns = (x2 / x1);
								}
								else
								{
									correctAns = (x1 / x2);
								}
								break;
						}
						break;
					case "ADD":
						proType = "+";
						correctAns = (x1 + x2);
						break;
					case "SUB":
						proType = "-";
						correctAns = (x1 - x2);
						break;
					case "MULT":
						proType = "*";
						correctAns = (x1 * x2);
						break;
					case "DIV":
						proType = "/";
						if(x2 < 1 || x1 != x2)
						{
							correctAns = (x2 / x1);
						}
						else
						{
							correctAns = (x1 / x2);
						}
						break;
					default:
						break;
				}

				System.out.print("\n| Level: " + level + "  |  Problem Type: "
						+ maths);
				System.out.print(" | ");

				System.out.print("Question " + (i + 1) + " / 10 ");

				System.out.println();
				genQuest(x1, x2, proType);
				System.out.print(" Your answer:  ");
				answer = scan.nextInt();
				genResponse(correctAns, answer);
				System.out.println();
				if(answer == correctAns)
				{
					++grade;
				}

			}
			reset = Reset();
		}
		while(reset != 1);

		int newGrade = grade * 10;

		if(newGrade >= 75)
		{

			System.out.println("\n Score: " + newGrade + "%\n"
					+ " Congratulations, you are ready to go to the next level!");
		}
		else
		{
			System.out.println(" Please ask your teacher for extra help. \n");
		}
		System.out.print(" Press 1 to begin a new session: ");
		int newSession = scan.nextInt();
		if(newSession == 1)
		{
			System.out.print("\n\n");
			new App();
		}
		else
		{
			System.out.println("Good bye!");
		}

		scan.close();
	}

	private int Reset()
	{

		return 1;
	}

	private int getRanNum(int n)
	{
		SecureRandom rand = new SecureRandom();
		return rand.nextInt(n);
	}

	private int genRNum()
	{
		SecureRandom rand = new SecureRandom();
		int seed = 0;
		switch(level)
		{
			case 1:
				seed = 10;
				break;
			case 2:
				seed = 100;
				break;
			case 3:
				seed = 1000;
				break;
			case 4:
				seed = 10000;
				break;
		}

		return rand.nextInt(seed);
	}

	private void genQuest(int n1, int n2, String pt)
	{

		System.out.print(" How much is " + n1 + " " + pt + " " + n2 + "?\n");
	}

	private String problemType(int n)
	{

		String PrTy = " ";

		switch(n)
		{
			case 1:
				PrTy = "ADD";
				break;
			case 2:
				PrTy = "SUB";
				break;
			case 3:
				PrTy = "MULT";
				break;
			case 4:
				PrTy = "DIV";
				break;
			case 5:
				PrTy = "RANDTYPE";
				break;
		}
		return PrTy;
	}

	private void genResponse(int correctAns, int answer)
	{
		Random rand = new Random();
		int count;
		count = rand.nextInt(4);
		//Checking if the answer is right
		if(answer == correctAns)
		{

			System.out.print(" Right Answer, ");
			switch(count)
			{
				case 0:
					System.out.println(" Very Good! ");
					break;
				case 1:
					System.out.println(" Excellent! ");
					break;
				case 2:
					System.out.println(" Nice work! ");
					break;
				case 3:
					System.out.println(" Keep up the good work! ");
					break;
			}
			System.out
					.print("_^_^_^_^_^_^_^_^_^_^_^_^_^_^_^_^_^_^_^_^_^_^_^_^_");
		}
		else
		{

			System.out.print(" Wrong Answer, ");
			switch(count)
			{
				case 0:
					System.out.println(" Please try again.");
					break;
				case 1:
					System.out.println(" Try once more. ");
					break;
				case 2:
					System.out.println(" Don’t give up!");
					break;
				case 3:
					System.out.println(" Keep trying.");
					break;
			}

			System.out
					.print("_._._._._._._._._._._._._._._._._._._._._._._._._._");
		}
	}

	public static void main(String[] args)
	{
		App app = new App();
	}
}

the key is to use a constructor App(), also setting the variable level in the scope of the class so that when startApp is run, the variable can be set in there.