multiply 2 numbers in Assembly language

.model small
.stack 100h
.code
start:
mov ah,1h
int 21h
sub al,30h

mov bh,al

mov ah,1h
int 21h
sub al,30h

mul bh

mov dl,al
add dl,30h

mov ah,2h
int 21h

mov ah,4ch
int 21h
end start