It is my experience that they don't normally cover (6 X (2/3)) or , or "order of operations" in a high school class- they expect you to have learned things like that in elementary school! What does your equation become if you replace (6 X (2/3)) with 4 and with 4?
Do you know what and are?
The "order of operations" can be remembered as "PEMDAS" (sometimes "Please Excuse My Dear Aunt Sally"). Any operations inside Parentheses before the parentheses are combined with other numbers, Exponents are dealt with before Multiplication or Division which are done before Addition or Subtraction.