Basic Arthmetic
You can do basic calculations like: 2+3, 2-3, 2*3, 3/2, 2^3, 5*(2-6).
Constants
The calculator knows the constants pi and e.
Functions
You can use the functions sin, cos, exp, log, log10.
Factorials
Conveniently it knows factorials, e.g. 5!.
Temporary variables
You can set the value of a variable and use it later. You do this by separating multiple expressions by semicolons.
Try the following: x=5; y=6; x*y
x=3; y=x^2+1; z=(x+1)/y; z
Much More!
The features are quite extensive. See Mathjs documentation.