Question 152740
You must apply the "order of operations". 
A memory technique used by many is "PEMDAS" an acronym for
"Please Excuse My Dear Aunt Sally" which stands for:
P -- parentheses first
E -- exponents
MD -- multiplication/division from left to right
AS -- addition/subtraction from left to right
.
1/3 (1/2 x 3 1/3)- 5/6
Start by converting 3 1/3 to a mixed fraction of 10/3
1/3 (1/2 x 10/3)- 5/6
Parenthesis first:
1/3 (10/6)- 5/6
Multiplication next:
10/18 - 5/6
Now, convert the right to to a common denominator of 18:
10/18 - 15/18
Do the subtraction:
-5/18 (this is your answer)