Part of the Fortran WikiBook

Fortran has the following arithmetic operators:

+ addition

- subtraction

* multiplication

/ division

** exponentiation (associates right-to-left)

Here are some examples of their use:

 i = 2 + 3   ! sets i equal to 5
 i = 2 * 3   ! sets i equal to 6
 i = 2 / 3   ! sets i equal to 0, since 2/3 is rounded down to the integer 0, see mixed mode
 x = 2 / 3.0 ! sets x approximately equal to 2/3 or 0.666667
 i = 2 ** 3  ! sets i equal to 2*2*2 = 8

Fortran has a wide range of functions useful in numerical work, such as sin, exp, and log. The argument of a function must have the proper type, and it is enclosed in parentheses:

 x = sin(3.14159) ! sets x equal to sin(pi), which is zero

The intrinsic math functions of Fortran are elemental, meaning that they can take arrays as well as scalars as arguments and return a scalar or an array of the same shape:

 real :: x(2), pi=3.14159
 x = sin([pi, pi/2])

The above program fragment sets the two elements of array x, x(1) and x(2), equal to sin(pi) and sin(pi/2) respectively.