If you are able to calculate the sum you already have the average, since:
media = suma / 10
To calculate the largest and the least you can create two variables and at each iteration the loop checks if the current number is greater than the largest and less than the smallest to update the value. For example:
float numero, mayor, menor, suma;
int i;
printf("Dame un número: ");
scanf("%d\n", &numero);
mayor = menor = suma = numero;
for (i = 1; i < 10; i++)
{
printf("Dame un número: ");
scanf("%d\n", &numero);
suma += numero;
if (numero > mayor)
mayor = numero;
else if (numero < menor)
menor = numero;
}
media = suma / 10;
I have not tried it, but you can get an idea by reading this code how to do it.