Certainly Roberto,
STACK, as a question type, really expects students to type an algebraic expression. We expect students to learn to type their answer, but the input mechanism is flexible and the validation step has been tried and tested for a wide range of students (age and experience). We have multiple choice as well (randomly generated mathematical
MCQ has a place). STACK is not designed with very young students in mind, but if people need new features tuned for younger students then I'm open to a conversation.
If you want to chat in person, email me at Edinburgh.
Chris Sangwin