Tracy,

>Also, -2 can indeed be expressed as 0-2, but there were no parenthesis in the original function posed and there should have been to be explicit. You can not arbitrarily add parenthesis to one and not the other when no parenthesis existed.

If you change the operand -2 to the expression 0-2 or 2-4 or 4-6 you must add parens. The parens would not be required if only addition and subtraction were involved in the original statement.

Later update forget exponentiation

7 - 5 * 4

If you substitute 3 + 2 in for 5 then it is incorrect to not add parens

7 - 3 + 2 * 4

parens must be used to get the correct value

7 - ( 3 + 2 ) * 4

You can always insert as many parens to an expression as you want, provided that you insert them correctly

( 7 - ( ( (3) + (2) ) * (4) ) )