I used the registered version of the Simply Fortran compiler, here: simplyfortran-3.0.msi, simplyfortran-2.35.msi; also, try the online Fortran compiler.
PROGRAM Sum
! inhibit older feature
IMPLICIT NONE
! declare numbers
REAL X,Y,Z
! input X
PRINT *,"Enter first number: "
READ *, X
! input Y
PRINT *,"Enter second number: "
READ *, Y
! perform calculation
Z = X + Y
! output sum
PRINT *,"Sum of X + Y = ", Z
READ(*,*)
END PROGRAM Sum
Output
Notes
Learn more, Fortran language
https://pinetools.com/syntax-highlighter
Types of Variables
Integer: It can hold only integer values.
Real: It stores the floating point numbers.
Complex: It is used for storing complex numbers.
Logical: It stores logical Boolean values.
Character: It stores characters or strings.