Income Property Analysis

A basic spreadsheet that allows me to load Cell A, B, C, E and I with numbers. For D it is the result of C X B equaling a number and B - that number to populate D. E is a loaded interest rate and I need F to be a standard mortgage calculator that derives a monthly payment using that interest rate from E then multiplying X 12 for an annual total payment. G is 1.25 X B. H = F + G. Load I with a number. J = I - H. Make sense?