Γκρίζα μαλλιά καθηγητής κάθεται σε τραπέζι στην αίθουσα διαλέξεων και κρατώντας το βιβλίο - Φωτογραφίες & Εικόνες Αρχείου

Grey hair professor standing in lecture room and looking at camera

Grey hair professor pointing on something at blackboard

Grey hair professor pointing on something at blackboard

Grey hair professor holding stack of books

Process for each solution. bearded lecturer man explain geometry. back to school. Math graphic tools. trigonometry lesson in classroom. get knowledge here. senior man teacher use math tools.

Senior lecturer standing between falling crumpled pieces of paper

Smiling grey hair professor holding stack of books with apple on top

Senior lecturer holding piece of chalk and looking away

Classic subjects learning. Improve teaching skills. Mature pedagogue. Teaching has changed in last years. Man bearded tutor in classroom. Teaching is passion. Main task in teaching. Formal education.

Handsome grey hair man holding book and looking at camera at home

Smiling senior man looking at camera while touching jacket isolated on grey

Senior man using headphones and smartphone on chair on grey background

Senior man smoking cigar and drinking whiskey in armchair

Close-up portrait of senior man reading book

Handsome grey hair man sitting in armchair, holding old photos and looking away

Sad senior man embracing photo album near window

Thoughtful senior writer sitting at workplace and looking away isolated on black

Thoughtful senior man in jacket looking at camera isolated on grey

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