irb(main):003:0> "6 things" =~ /(^|\s)6(\s|$)/
=> 0
irb(main):004:0> "things like 6" =~ /(^|\s)6(\s|$)/
=> 11
irb(main):005:0> "6" =~ /(^|\s)6(\s|$)/
=> 0
irb(main):006:0> "non-six" =~ /(^|\s)6(\s|$)/
=> nil