一.数学中常用符号+: plus X: multiply-: subtract ÷: divideV~: square root |...|: absolute value=: is equal to =/=: is not equal to>: is greater than =: is greater than or equal to (或 no less than)<=: is less than or equal to (或no more than)二.表达相应数目的前缀1:uni-,mo