8086 Programming

How to add two numbers?

TITLE ADD
.MODEL SMALL
.STACK 32
.DATA
VAL1 DW 1234H
VAL2 DW 4321H
SUM DW ?
.CODE
MAIN PROC FAR
MOV AX,@DATA
MOV DS,AX

MOV AX,VAL1
ADD AX,VAL2
MOV SUM,AX

MOV AX,4C00H
INT 21H
MAIN ENDP
END MAIN