We're not talking very small. Is it the compiler? I'm using gfortran. An example would be: f(y)=1E-5*(y**3) For f(40), that should be 0.64. When I compile and execute, however, it displays 0's. If I make the coefficient 1, the result does come out to be correct. I have an old Fortran IV (I'm using F77) book that says for that version of the code, I can't do 1.E-76. This is well closer to 1 than that. They even used an example where the power of 10 was -21. So is this right? Is it a problem with the compiler?