First remove the parenthesis.
5/6 - 2/3
Then we want the least common denominator which is 6 because 2 * 3 = 6.
Now we want to adjust the fractions based on our LCD.
So 5/6 - 2 * 2/6
Now since the denominators are equal we can combine the numerators.
So 5 - 2 * 2/6
First multiply 2 by 2 to get 4. Our expression then becomes 5 - 4/6 which translates to 1/6.
Hope this helps!