FIRST_ASSEMBLY

.MODEL SMALL
.STACK 100H
.DATA
A DW 2
B DW 5
SUM DW ?
.CODE
MAIN PROC
    ;initialize DS
    MOV AX,@DATA
    MOV DS,AX
    ;add the numbers
    MOV AX,A  ;AX has A
    ADD AX,B  ;AX has A+B
    MOV SUM,AX ;SUM=A+B

    ;exit to DOS
    MOV AX,4C00H
    INT 21H
    MAIN ENDP
END MAIN