Example: △ABC∽△DEF, which means "triangle ABC is similar to triangle DEF."

Congruence: It has been explained in the discipline that if two figures have the same shape, they are congruent, which can be read as "all equal" with the symbol "".

For example: △ ABC△ a' b' c'

Reading: All triangles ABC are equal to triangles A'B'C')

Operation symbol

Such as plus sign (+), minus sign (-), multiplication sign (× or), division sign (÷ or/), union of two sets (∩), intersection (∩), root sign (∩ ~), logarithm (log, lg, ln,