Graue Haare Professor zeigt auf etwas mit dem Finger auf Tafel - Stockfoto & -bild

Grey hair professor pointing on something with pencil on blackboard

Happy senior lecturer holding paper plane in hand

Pensive grey hair professor standing at blackboard with piece of chalk

Grey hair professor pointing on something with wooden pointer

Grey hair professor correcting something at blackboard

Grey hair professor drawing with piece of chalk at blackboard

Happy senior lecturer with open arms standing near blackboard

Rear view of senior lecturer writing something on blackboard with piece of chalk

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

Cropped image of professor drawing with piece of chalk at blackboard

Cropped view of man with chalk writing numbers on blackboard

Cheerful schoolchild adjusting eyeglasses near chalkboard with mathematic equations

Cropped view of man writing numbers with chalk on blackboard

Excited schoolgirl in eyeglasses showing idea gesture near chalkboard with equations

Preteen schoolgirl pointing with pen at mathematic equations on chalkboard

Offended schoolgirl standing with crossed arms near chalkboard with equations