Creating VBA codes to do what formulas do

I have attached the workbook I am working with.

The problems and objectives are located on the first sheet.

Any assistance is appreciated.

The cells themselves need to be edited at times and by inputing data into these cells, wouldn't the formula be deleted from the cell?

This is a sheet for some older people that aren't necessarily computer literate, so using the vba over formulas would ensure that the sheet would still function properly no matter what the user input or deleted (as far as information within cells).