Ключевые слова: blackboard, chalk, chalkboard, cheerful, chemistry, classroom, college student, computer graphic, digital, digital tablet, digitally generated, doodle, education, equation, hand drawn, happy, higher education, icon, learning, light bulb, math, microscope, notepad, pile, portrait, school, science, scrolling, smiling, tablet, tablet computer, tablet pc, test tube, touching, touchscreen, university student, using, white,