Instead symbols like + or * are used to define functions that can do things like normal numerical addition and subtraction.
相反，使用 + 或 * 等符号定义可以执行普通数字加减法的函数。
2
Ratio - the kilogram scale is an example of a ratio scale — the symbols that are assigned to object attributes have numerical meaning.
定比尺度(ratio)—千克尺度是定比尺度的一个示例？分配给物体属性的符号具有数字意义。
3
You can perform various operations on those symbols (such as computing ratios) that you cannot perform using numerical values obtained using less powerful measurement scales.