主要符号

＋ plus ;positive

－ minus ;negative

× multiplied by ;times

÷ divided by

＝ equals

≈ approximately equals

≠ not equal to

＜ less than

＞ greater than

≤ equal to or less than

≥ equal to or greater than o

( ) round brackets; parentheses

[ ] square brackets

{ } braces

∈ is a member of the set

⊂ is a subset of

∽ similar to

≌ congruent to

* denotes an operation

∴ therefore

∵ because

∶ ratio sign, divided by, is to

∷ equals, as(proportion)

∥ parallel to

⊥ perpendicular to, at right angles with

∠ angle

∟ right angle

º degree

′ minute

″ second

⊙ circle

A⁀B arc AB

e: the base of natural logarithms,approx.2.71828

x! factorial x, x(x-1)(x-2)---1

log_nx log x to the base n

π pi

lnx log x to the base e(natural logarithm)

lgx log x to the base 10(common logarithm)

|x| the absolute value of x