计算数学表达式

Evaluates simple math expression like 2*4 or 10/2 and outputs its result. You can use \ operator which is equivalent to round(a/b).

计算简单的数学表达式，比如2*4 或 10/2，并输出结果。\ 操作符结果同 round(a/b)。

Very useful in CSS where numeric values should be modified frequently.

当数字值频繁改变时这个比较很有用。