Siwe włosy profesor wskazuje na coś z drewnianymi wskaźnik - Zdjęcie stockowe & obraz

Happy senior lecturer holding paper plane in hand

Grey hair professor pointing on something with finger at blackboard

Pensive grey hair professor standing at blackboard with piece of chalk

Grey hair professor pointing on something with pencil on blackboard

Grey hair professor looking at students rising hands

Happy senior lecturer with open arms standing near blackboard

Grey hair professor correcting something at blackboard

Tired grey hair professor touching eyes at blackboard

Cropped image of senior professor pointing on something with pencil on blackboard

Cropped image of professor drawing with piece of chalk at blackboard

Positive senior man talking on smartphone and pointing with finger isolated on grey

Cheerful schoolchild adjusting eyeglasses near chalkboard with mathematic equations

Smiling elderly man in eyeglasses and bow tie looking at camera isolated on grey

Elderly man in bow tie and blue jacket using smartphone isolated on grey

Excited schoolgirl in eyeglasses showing idea gesture near chalkboard with equations

Cropped shot of senior man with pencil and sheet of paper