For simple math symbols, you can use http://math.typeit.org and copy and paste symbols into Edmodo.
For more advanced symbols and equations, you can use LaTeX, a system that formats symbols on Edmodo. Just type [math], then a LaTeX code, then [/math]. For example, Edmodo will show the formula shown in the left column below if you send a note with the text shown in the right column.
There are a number of good resources on the web available to help you identify the LaTeX symbol for each math equation:
- Our favorite quick start guide to LaTeX: http://mathim.com/static/chatprimer.html
- More LaTeX commands: http://edmodoteacherhub.wikispaces.com/file/view/LatexEdmodoVersion4.pdf
- A video on how to use LaTex in Edmodo: http://www.youtube.com/watch?v=1A-E67hZun4
- SciWeavers LaTex Equation Editor can easily generate LaTeX expressions for you: http://www.sciweavers.org/free-online-latex-equation-editor