I woke up this morning thinking the same as Richard. Madruga's 4 extra combination are legitimate & different.
What I also realized is Madruga is fundamentally changing the rules of the game since he is permitting nested parenthesis. Note in all examples of the school game on the web, there is either a template or rules that don't permit nested parenthesis or multiple operaters between numbers.
While your rules might permit nested parenthesis most of us picked up on the fact you wanted us to solve the standard school template. You might clarify this point.
