Question 1204585
<br>
Tutor @ikleyn has again tried to show her superiority by posting a response that says the problem should have been to insert parentheses so that the given statement was true.<br>
That is absolute hogwash -- as are many of her posts where she tries to correct the statement of the problem, or to disparage the responses from other tutors.<br>
There is no need to add any parentheses to make the given statement true.<br>
Standard order of operations means you do the multiplications and/or divisions before you do the additions and/or subtractions.<br>
So the first operation in the expression on the left is 42/2, which is 21.<br>
After that, the expression is 6+21-15, which is equal to 12 -- so the statement as posted is correct.<br>
There is no need for adding parentheses...<br>