# Unexpected Answer for an Equation

Hello,

I am trying to calculate the following equation in SAGE.

N = 100.

p = 0.9.

r = (N /(N-1))*(ln(N)-ln(-ln(p))); r

Unfortunately, sage gives this answer **100/99*log(100) + 2.27309831041661** , which is not the expected answer !!

But, when I used google calculator, I got the expected answer, which is **6.92478536697**

Please let me know what is going on.? Thank you.

To add to the answer below, note that if you enter

`N`

as a floating-point number, you directly get what you want:Thank you Bruno.