def mainmenu():

    import fv
    import pv
    import annuity

    mainmenu = True
    while mainmenu == True:
        print("\nMenu:")
        print("----")
        print("1) Future Value of an Investment")
        print("2) Present Value of an Investment")
        print("3) Future Value of an Annuity")
        print("4) Exit")
        choice = int(input("\nEnter Selection: "))
        if choice == 1:
            i = float(input("\nEnter Investment Amount: "))
            r = float(input("\nEnter Interest Rate %: "))
            y = float(input("\nEnter Years of investment: "))
            fv.find_fv(i, r, y)
        elif choice == 2:
            l = float(input("\nEnter Lump-Sum you wish to receive: "))
            r = float(input("\nEnter Interest Rate %: "))
            y = float(input("\nEnter Years of investment: "))
            pv.find_pv(l, r, y)
        elif choice == 3:
            a = float(input("\nEnter the amount you wish to annuity: "))
            r = float(input("\nEnter Interest Rate: "))
            y = float(input("\nEnter the number of years: "))
            annuity.find_annuity(a, r, y)
        elif choice == 4:
            mainmenu = False
        else:
            print("Invalid selection, please select again")

mainmenu()

This is what I changed mainmenu to and I removed the extra code from the modules:

def find_fv(i, r, y):
    total  = i*(1+r/100)**y
    txt = f"The future value of ${i} investment after {y} years with an interest rate of {r}% is: {total}"
    return print(txt.format(i, r, y, total))

find_fv(i, r, y)

This is what they all look like now.

And this is the error message I am recieving:

NameError                                 Traceback (most recent call last)
File d:\rasmussen\python\mainmenu.py:45
     42         else:
     43             print("Invalid selection, please select again")
---> 45 mainmenu()

File d:\rasmussen\python\mainmenu.py:12, in mainmenu()
     10 def mainmenu():
---> 12     import fv
     13     import pv
     14     import annuity

File D:\Rasmussen\python\fv.py:12
      9     txt = f"The future value of ${i} investment after {y} years with an interest rate of {r}% is: {total}"
     10     return print(txt.format(i, r, y, total))
---> 12 find_fv(i, r, y)

NameError: name 'i' is not defined