Order of operations. Brackets
  If  brackets are absent, the following
  
   order of operations
  
  is right:
  
  1)   raising to a power and extraction of a root (one after another);
  
  2)   multiplication and division (one after another);
  
  3)   addition and subtraction (one after another).
  
  If  brackets are present,
  
   at first all operations inside brackets are executed
  
  according to the aforesaid order, and
then      the rest of the operations out of  brackets are executed (in the same order).
 
  E x a m p l e . Calculate the next  expression:
  
  
  ( 10 +      2
  
   
    3
   
  
  
  
  
   ·
  
  
   3 ) + 4
  
  
   
    3
   
  
  
   –  ( 16 : 2  – 1 )
  
  
   ·
  
  
   5 –      150 : 5
  
  
   
    2
   
  
  
   .
  
 
  S o l u t i o n .  At first, powers must be calculated and changed by theirs values:
  
  
  ( 10 +      8
  
   ·
  
  
   3 ) + 64 – ( 16 : 2 – 1 )
  
  
   ·
  
  
   5
– 150 : 25 ;
  
 
  after this,  
   multiplication and division in the brackets and out of
  
  them are executed:
  
  
  ( 10 + 24 ) + 64 – ( 8 – 1 )
  
   ·
  
  
   5 – 6 ;
   
   
   now, additions
and      subtractions in the brackets are executed:
   
   
   34 + 64 – 7
  
  
   ·
  
  
   5 –      6 ;
   
   
   finally, after
the      rest of the multiplication 7
  
  
   ·
  
  
   5
= 35 we receive:
   
   
   34 + 64
  
  
   –
  
  
   35 – 6 = 57 .