Can you please explain using excel. Please show how I would be able to enter into excel myself. Thank you

1. Buy a stock, sell a stock, receive a dividend calculate the return HPR% (margin, selling short or outright) a. Example: Buy $100, sell $120, receive div $4 - calculate HPR%= HPR%=(CF/I) (120-100+4)/100 = 24/100 = 24% b. Example: The same numbers with 50% margin loan @10% interest): (120-50-5+4-50)/50 = 19/50 = 38% c. Short Selling: Borrow shares and sell at $100. Buy back all shares at $80 - calculate HPR%= 100-80/100 = 20%