#include <stdio.h>

#include <conio.h>

#include <math.h>

int main()

{

            int a, b, c, d;

            float TB;

            printf("nhap 4 so a, b, c, d: ");

            scanf("%d%d%d%d", &a, &b, &c, &d);

            TB = (float)(a+b+c+d)/4;

            printf("trung binh cong cua 4 so la: %f", TB);

            getch();