= Precedence From highest to lowest, this is the precedence table for ruby. High precedence operations happen before low precedence operations. !, ~, unary + ** unary - *, /, % +, - <<, >> & |, ^ >, >=, <, <= <=>, ==, ===, !=, =~, !~ && || .., ... ?, : modifier-rescue =, +=, -=, etc. defined? not or, and modifier-if, modifier-unless, modifier-while, modifier-until { } blocks Unary <code>+</code> and unary <code>-</code> are for <code>+1</code>, <code>-1</code> or <code>-(a + b)</code>. Modifier-if, modifier-unless, etc. are for the modifier versions of those keywords. For example, this is a modifier-unless expression: a += 1 unless a.zero? <code>{ ... }</code> blocks have priority below all listed operations, but <code>do ... end</code> blocks have lower priority. All other words in the precedence table above are keywords.