英文關鍵字
algebra
art
background
board
business
cancel
childhood
class
classroom
clean
colorful
concept
copy
creative
creativity
design
draw
drawing
drawn
education
elementary
equals
equation
error
formula
free
hand
idea
keep
learn
learning
lesson
mathematic
mathematical
mistake
number
object
office
paint
plus
price
school
sign
symbol
two
white
word
write