Arithmetic Quiz with Score Counter 1.2.2

package practice.programpractice;
import java.util.*;
public class switchQuiz {

    //Author Zunder Jacob A. Pacis
    // 1.2.2

    public static void main(String[] args) {

        Scanner sc = new Scanner(System.in);
        System.out.println("How many items do you want to answer?");
        byte item = sc.nextByte();
        byte i;
        System.out.println("What math operation do you want to solve?\n1 - addition\t\t2 - subtraction\n3 - multiplication\t4 - division");
        byte operator = sc.nextByte();
        int score = 0;
        switch (operator) {
            case 1 -> {
                System.out.println("You have chosen Addition!\n");
                for (i = 0; i < item; i++) {
                int a = (int) (Math.random() * 11);
                int b = (int) (Math.random() * 11);
                int itemNo = i + 1;
                System.out.println(itemNo + ". What is " + a + " + " + b + "?");
                int ans = a+b;
                int input = sc.nextInt();
                if (input==a+b) {
                    System.out.println("Your answer is correct!");
                    score++;
                 }
                else System.out.println("Your answer is wrong!, the correct answer is " + ans);
                 }
                 }
            case 2 -> {
                System.out.println("You have chosen Subtraction!\n");
                for (i = 0; i < item; i++) {
                int a = (int) (Math.random() * 11);
                int b = (int) (Math.random() * 11);
                int itemNo = i + 1;
                System.out.println(itemNo + ". What is " + a + " - " + b + "?");
                int ans = a-b;
                int input = sc.nextInt();
                if (input==a-b) {
                    System.out.println("Your answer is correct!");
                    score++;
                 }
                else System.out.println("Your answer is wrong!, the correct answer is " + ans);
                 }
                 }
            case 3 -> {
                System.out.println("You have chosen Multiplication!\n");
                for (i = 0; i < item; i++) {
                int a = (int) (Math.random() * 11);
                int b = (int) (Math.random() * 11);
                int itemNo = i + 1;
                System.out.println(itemNo + ". What is " + a + " x " + b + "?");
                int ans = a*b;
                int input = sc.nextInt();
                if (input==a*b) {
                    System.out.println("Your answer is correct!");
                    score++;
                 }
                else System.out.println("Your answer is wrong!, the correct answer is " + ans);
                 }
                 }
            case 4 -> {
                System.out.println("You have chosen Division!\n");
                for (i = 0; i < item; i++) {
                int a = (int) (Math.random() * 11);
                int b = (int) (Math.random() * 11);
                int itemNo = i + 1;
                float c = a;
                float d = b;
                System.out.println(itemNo + ". What is " + a + " ÷ " + b + "?");
                float ans = c/d;
                float input = sc.nextFloat();
                if (input==c/d) {
                    System.out.println("Your answer is correct!");
                    score++;
                 }
                else System.out.println("Your answer is wrong!, the correct answer is " + ans);
                 }
                 }
            default -> System.out.println("Enter a valid input!");
         }

          //continuation
                if (operator <= 4 && operator >=1) {
                System.out.println("\nYour total score is " + score + " out of " + item);
                double s = score;
                double it = item;
                double grade = s / it;
                if (grade==1)
                    System.out.println("\nPerfect Score!");
                else if (grade >= 0.75 && grade < 1)
                    System.out.println("\nExcellent!");
                else if (grade >= 0.5 && grade < 0.75)
                    System.out.println("\nGood");
                else if (grade >= 0.25 && grade < 0.5)
                    System.out.println("\nTry Again");
                else if (grade >= 0 && grade < 0.25) {
                    System.out.println("\nBetter Luck Next Time");
                } else {
                }
         }
    }
}