GRE数学部分用到的主要符号

　　据留学360介绍，GRE数学部分用到的主要符号 ＋ 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 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