C :

#include <stdio.h>
int main(void)
{
long int a,b,c,t=10,i=0;
scanf("%ld=%ld",&a,&c);
while (a/t)
{
b=a%t;
if (a/t+b==c) {
printf("%ld+%ld=%ld\n",a/t,b,c);
t*=10;i++;
}
else t*=10;
}
if (i==0) puts("Impossible!");
return 0;
}

Python :

a,b=input().split("=")
n=len(a)
for i in range(1,n):
    if int(a[0:i])+int(a[i:n])==int(b):
        print ("%s+%s=%s"%(a[0:i],a[i:n],b))
        break
else:
    print("Impossible!")