In Fortran, the absolute value of a number can be obtained using the ABS function.
The ABS function returns the absolute value of its argument.
Example
program AbsoluteValueExample
implicit none
integer :: x
real :: y
x = -10
y = -3.14
write(*,*) "Absolute value of x:", ABS(x)
write(*,*) "Absolute value of y:", ABS(y)
end program AbsoluteValueExample