40s
academic
adult
algebra
algebraic
alphabet
black
board
caucasian
chair
chalk
chalkboard
class
classroom
desk
education
educational
equation
formal
formula
geometry
greenboard
hand
high
indoor
knowledge
letter
male
man
math
mathematics
mature
men
occupation
one
people
problem
profession
raised
school
shirt
side
standing
teacher
teaching
tutor
university
writing