> Just checking
>
> if I have
>
> a = a - b*c
>
> b*c gets calculated first then that result is subtracted from a ?
> In other words, parantheses, in Ruby, is not necessary to make that
> calculation ?

Table of ruby operators and their precedence:
http://phrogz.net/ProgrammingRuby/language.html#table_18.4