Removing the brackets across -27.0 does the trick, though would need to find the logic behind the same (-27)**(1/3.0) gives NaN -27**(1/3.0) gives -3 Regards, Raghav -----Original Message----- From: jzakiya [mailto:jzakiya / mail.com] Sent: Friday, December 18, 2009 12:15 PM To: ruby-talk ML Subject: Math errors (-3)**3 => -27 (-27)**(1/3.0) give NaN instead of -3 All odd roots (1/3,1/5,1/7 etc) of negative numbers should give negative root values, as above, but ruby (in irb) gives NaN (not a number), even when I require 'complex' . Is this considered an error in Ruby?