Need help in creating a form with drop downs

Hi Experts, really need some help for my cake shop. Have attached an excel file - how I want my database to look. But I need a front end form for the same which will have drop downs for the cake names. The discount given when entered by my employee should be auto calculated in the selling price (which will be fetched from the second sheet). Can someone help me do this? I would be really greatful.Copy of Cake_Street_Inflow_Outflow.xlsx

Thanks for your quick response. No, the discount need not be in percentage

Can someone please assist on this?