How To Add Two Numbers In Same Row Of A File

I need to add two integers in the same row of a file, separated by tab

my file abc.txt has the following entry

12 123
15 456

My program needs to add 12 with 123 and 15 with 456

I am being able to split the two entries in a row and convert them to integer but i dont know how to treat them as separate numbers and add them. For example if i try to add then 12 adds with 12 and 123 adds with 123. wheres it should be 12+123

Here is my program

import java.io.*;
public class test {
public static void main(String[] args) {
String s = "";
FileInputStream finp = null;

[Code] .....