1)#include <iostream>using namespace std;int main(){ int n; cout << "n = ", cin >> n; for (int i=10; i<100; i++) { if ((i/10==n)||(i%10==n)||(i%n==0)) cout << i << " "; } return 0;}Пример:n = 714 17 21 27 28 35 37 42 47 49 56 57 63 67 70 71 72 73 74 75 76 77 78 79 84 87 91 97 982.#include <iostream>using namespace std;int main(){ for (int i=1; i<10; i++) { for (int j=0; j<10; j++) cout << i*100+j*10+i << " "; } return 0;}Результат:101 111 121 131 ... 979 989 9993.#include <iostream>using namespace std;int main(){ int s = 0; for (int i=10; i<100; i++) { if ((i % 2 == 0)||(i % 10 == 7)) s +=i; } cout << "s = " << s; return 0;}Результат:s = 29434.#include <iostream>using namespace std;int main(){ int a, b, c, k = 0; for (int i=100; i<1000; i++) { a = i / 100; b = i / 10 % 10; c = i % 10; if ((a==b)||(a==c)||(b==c)) k++; } cout << "k = " << k; return 0;}Результат:k = 252