7.1

Factorial
import java.util.Scanner;

public class main {

    public static void main(String[] args) {

        Scanner scan = new Scanner(System.in);
        int n = Integer.parseInt(scan.nextLine());
        int result = 1;
        for (int i = 1; i<=n; i++){
            result = result*i;
        }
        System.out.println(result);
    }
}

Sum Digits
import java.util.*;

class Main {

    public static void main(String[] args) {
        Scanner scan = new Scanner(System.in);
        int a = scan.nextInt();
        int sum = 0;
        while(a>0){
            sum += a%10;
            a/=10;
        }
        System.out.println(sum);
    }
}