import java.util.Scanner; public class Main{ public static void main(String []args){ Scanner sc = new Scanner(System.in); int n = sc.nextInt(); int sum = 0; for(int i = 1; i <= n; i++){ if(i % 7 == 0){ sum += i; } } System.out.printf("%d",sum); } }这题用一个循环加判断就可以求解。