A few more different types of maths problems could see this becoming a great brain trainingish game, though not sure I'd be happy leaving a kid in the care of the creepy old flashing Wizard (though thankfully he's fully clothed underneath)
One bug though, the second level, Student Wizard, doesn't seem to work. Both the main menu button and the 'Next Level' button on Apprentice Wizard don't work. Checked the console and got this error:
Scene 'Level2' couldn't be loaded because it has not been added to the build settings or the AssetBundle has not been loaded.