How come number is being rounded in C?

#include<stdio.h>
#include<conio.h>

 void DisplayInstructions();
 int CalculateAverage(int a,int b, int c);
 float DisplayAnswer(float ans);

 void main()
 {
     int Integer1 = 0, Integer2 = 0, Integer3 = 0;
     float answer;
     DisplayInstructions();
     scanf_s("%d", &Integer1);
     scanf_s("%d", &Integer2);
     scanf_s("%d", &Integer3);
     answer = CalculateAverage( Integer1, Integer2, Integer3);
     DisplayAnswer(answer);
     _getch();
 }

 void DisplayInstructions()
 {
     printf("Enter 3 Integers seperated by the ENTER key\n");
 }

 int CalculateAverage(int a, int b, int c)
 {
     float average, num = 3;
     average = ( a + b + c )/num;

     return average ;
 }

 float DisplayAnswer(float ans)
 {
     printf("Answer=%f\n", ans);
 }