ADD & SUB IN assembly language

.MODEL SMALL
.STACK 100h
.DATA

A DB 4
B DB 5
C DB 3
D DB 1


.CODE

  MAIN PROC

    MOV AX, @DATA
    MOV DS, AX

    MOV AL, A
    MOV AL, B

    ADD AL, BL
    MOV DL, AL
    ADD DL, 48

    MOV AH, 2
    INT 21H

    MOV AH, 2
    MOV DL, 32
    INT 21H


    MOV AL, C
    MOV AL, D

    SUB AL, BL
    MOV DL, AL
    ADD DL, 48

    MOV AH, 2
    INT 21H



    MOV AH, 4CH
    INT 21H

  ENDP MAIN

END