No mistake in the equation above. anybody is welcome to solve the equation, but when anybody wants to answer it, math has its own rules/laws. equation given above, as it is, is a problem to be freely solved by every1, whoever/ whatever they are. if a couple of parentheses put somewhere in that equation, it becomes another different problem. when somebody solve it correctly, it means they know math well, otherwise, they don't. from this type of simple math, we will know how is some1 knowledge about basic math. and 0 is the correct answer to the equation above given by Qatarisun