N 0 1 2 3 1 2 3 or 0 1 2 3 3 2 1 0 1 2 3. Symbols save time and space when writing. In computer applications like Excel the symbols mean not equal.
Some math symbols are Greek and Latin letters dating back centuries to ancient times.
Micro or section. This is similar to but not exactly the same as equals. Mathematical symbols such as addition subtraction multiplication division equality inequality etc. M and s can take subscripts to show what you are taking the mean or standard deviation of.