The lines of the table are in order of precedence, so `a * b + 6' is interpreted as `(a * b) + 6'. When in doubt put brackets in!
The Associativity column shows how the operators group. E.g. `<' groups left to right, meaning that a<b<c is equivalent to (a < b) < c rather than a < (b < c). Both are pretty useless expressions.
Associativity  Operator 

left to right  () [], >, . 
right to left  ! (negation), ~ (bitnot) 
++, ,  (unary) , * (unary), & (unary), sizeof 

right to left  cast (type) 
left to right  *, /, % (modulus) 
left to right   + 
left to right  <<, >> 
left to right  <, <=, >, >= 
left to right  ==, != 
left to right  & (bitand),  (bitor) 
left to right  ^ (bitxor) 
left to right  && (logical and) 
left to right   (logical or) 
right to left  ?: 
right to left  =, +=, =, /=, %=, >>=, &= 
left to right  , 