+ 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
lognx 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
