$1.$ Write an $8051$ assembly language program using $$MUL$$ and $$DIV$$ instructions.

$2.$ Write an $8051$ assembly language program to generate a delay of $10$ ms using $$DJNZ$$ instruction.

$3.$ Write an $8051$ assembly language program to generate a pulse of $5$ms with duty cycle $40\%$ from p$1\mathrm{.}6$ using timer $1$ mode $0.$

$4.$ Write an $8051$ assembly language program to transfer $$VIT VIT VIT$$ at a baud rate of $2400$ with $8-$bit data.

$5.$ Write an $8051$ assembly language program to receive $8$ letters at $28800$ baud rate