User functions Wiris Quizzes Studio uses symbolic notation so we can work with variables and symbols. This is extremely useful but then f(x) is understood as a multiplication . If we want that to be interpreted as a function evaluated at a point , we need to declare it as a User function in Validation > General > Options for general. Let us see a question example This is the well-known statement of the Fibonacci sequence. We ask for two answers: the relation and a particular term of the series. Thus, the Correct answer tab will look like Note that since is marked as a User function, it is shown in blue, as any other elemental function (). This feature is also useful when considering composition of functions questions.