Addition


Outline:
                          ?????
                           XXXXX
                           YYYYY 
                          ?AAAAA

The "?" are possible carries. 
In general, the column calculations must be  sequential.

#include <stdlib.h>
#include <stdio.h>
#include <math.h>
#include <string.h>
int a[5]={7,3,5,4,6},b[5]={9,2,7,8,5},carry[6],ans[6];
int i;

int main(int argc, char* argv[]){

    carry[5]=0;
    i=4;
    while (i>-1) {
        ans[i+1]=a[i]+b[i]+carry[i+1];    //array element interactions
        if (ans[i+1]>=10) {
            ans[i+1]=ans[i+1]-10;
            carry[i]=1;

        } else {
            carry[i]=0;
        }
        i--;
    }
    ans[0]=carry[0];
    printf("%d%d%d%d%d+%d%d%d%d%d=", a[0],a[1],a[2],a[3],a[4],b[0],b[1],b[2],b[3],b[4]);
    if (ans[0]==1)printf("1");
    i=1;
    while (i<6) {
        printf("%d", ans[i]);
        i++;
    }

    printf("\n");
    return 0;
}