Mathematics - Functions - Introduction - Understanding functions - The Magic Machine

Show a 'machine' graphic with an input hopper and output chute. The student types a number into the input. The machine processes it and outputs a result. The rule is hidden (e.g., 'double and add 1'). After trying several inputs (1→3, 2→5, 3→7, 4→9), the student guesses the rule. Provide 3 different