C :

# include <stdio.h>
int main ()
{
  int a, b, sum;
  a = 123 ;
  b = 456 ;
  sum = a + b ;
  printf("sum=%d\n", sum );
  return 0;
}

C++ :

#include<iostream>
using namespace std;
int main()
{
	int a=123,b=456,sum=0;
    sum=a+b;
	cout<<"sum="<<sum;
	return 0;
}

Pascal :

begin write('sum=579');end.

Python :

# coding=utf-8
a, b = 123, 456
sum = a + b
print("sum=", sum, sep = '')