.MODEL SMALL
.STACK 200h
.DATA
    PROMPT_1 DW 0DH, 0AH, 'ENTER THE FIRST NUMBER: $'
    PROMPT_2 DW 0DH,0AH , 'ENTER THE SECOND NUMBER: $'
    PROMPT_3 DW 0DH, 0AH, 'THE SUM OF TWO NUMBERS IS: $'
    PROMPT_4 DW 0DH, 0AH, 'THE DIFFERENCE OF TWO NUMBERS IS: $'
    NUM1 DB ?
    NUM2 DB ?
    RES DB ?
    RES1 DB ?
.CODE
START:
    MOV AX, DATA
    MOV DS, AX

    LEA DX, PROMPT_1
    MOV AH, 09H
    INT 21H

    MOV AH, 01H
    INT 21H

    SUB AL, 30H
    MOV NUM1, AL

    LEA DX, PROMPT_2
    MOV AH, 09H
    INT 21H

    MOV AH, 01H
    INT 21H

    SUB AL, 30H
    MOV NUM2, AL
    ADD AL, NUM1
    MOV RES,AL

    ADD BL, 30H

    LEA DX, PROMPT_3
    MOV AH, 09H
    INT 21H

    MOV DL, RES
    ADD DL, 30H
    MOV AH, 02H
    INT 21H

    MOV AL, NUM1
    SUB AL, NUM2
    MOV RES1,AL

    SUB BL, 30H

    LEA DX, PROMPT_4
    MOV AH, 09H
    INT 21H

    MOV DL, RES1
    ADD DL, 30H
    MOV AH, 02H
    INT 21H

    MOV AH, 4CH
    INT 21H
END START