; Read the first number
LEER:
    MOV AH, 01H ; Service 01H for reading a character
    INT 21H     ; Store the ASCII code of the character in AL
    CMP AL, 30H ; Check if the digit is less than '0'
    JL LEER
    CMP AL, 39H ; Check if the digit is greater than '9'
    JG LEER
    SUB AL, 30H ; Convert ASCII to hexadecimal
    MOV NUM1, AL

; Read the second number
LEER2:
    MOV AH, 01H ; Service 01H for reading a character
    INT 21H     ; Store the ASCII code of the character in AL
    CMP AL, 30H ; Check if the digit is less than '0'
    JL LEER2
    CMP AL, 39H ; Check if the digit is greater than '9'
    JG LEER2
    SUB AL, 30H ; Convert ASCII to hexadecimal
    MOV NUM2, AL

; Addition
ADD AL, NUM1 ; NUM1 + NUM2
MOV SUM, AL  ; Store the result

; Subtraction
MOV AL, NUM1
SUB AL, NUM2 ; NUM1 - NUM2
MOV RES, AL  ; Store the result

; Multiplication
MOV AL, NUM1
MOV CL, NUM2
MUL CL  ; NUM1 * NUM2
MOV MULTI, AL ; Store the result

; Division
MOV AL, NUM1
MOV BL, NUM2
DIV BL ; NUM1 / NUM2
MOV COCI, AL ; Store the quotient
MOV RESI, AH ; Store the remainder