This command will open up a template that allows you to evaluate an expression in sigma notation.
This command is accessible by pressing ALPHA then WINDOW then 2.
This command is especially useful for statistics and algebra.
It is also available in the programming mode. You can access it either through the catalog or the same way specified above.
The syntax for this command is
Σ(Expression,Variable,Starting number,Ending number)
An example would be to determine the sum of 2*X for X going from 1 to 10.
It would look like this: