Code with function file not working

I'm writing a code to calculate investmenet after a certain amount of time, using the equation attached. (I've assumed Po is X in the code)

When I run the code, I get the error shown

Answer 1

[VBBV]

%if true
  P = X*(1+r/100).^t

Change this line by adding operators

[JaffaCakes]

Thanks I hadn't noticed this

Answer 2

[David Hill]

No reason for global variables. Problem is equation

P=X*(1+r/100)^t;%need X*

[JaffaCakes]

Thanks :)