deletions | additions       diff --git a/Box.tex b/Box.tex  index 14a663f..397776a 100644  --- a/Box.tex  +++ b/Box.tex 
...
$N =\overbrace{R}^{\sim10} \times \overbrace{f_p}^{\sim 1} \times \overbrace{n_e}^{\sim 0.2} \times \underbrace{f_l \times f_i \times f_c \times L}_{?}$  So the product of the first 3 terms, terms is  now well estblished, estblished and  is of order 1. So we can simplify the Drake equation and re-write it as $N \approx \underbrace{f_l \times f_i \times f_c \times L}_{?}$