英文關鍵字
2x2
addition
arithmetic
basic
beautiful
black
blackboard
board
caucasian
chalk
chalkboard
child
childhood
concept
cute
educate
education
elementary
example
figures
first
girl
hand
idea
kid
kindergarten
knowledge
learn
lesson
letter
math
mathematics
multiplication
numbers
practice
problem
school
simple
study
teacher
white
write
writing
young
youth