BCalc is a easy-to-use calculator for Nokia Series60. The main features:
http://shop.my-symbian.com/include/pictures/620053/hist1.jpg
usual enter method of the mathematical expressions, e.g: 1-epx(X^2)/2

drawing of function graphs

user-editable list of symbols/variables

editor history

built-in standard mathematical functions

This is Bcalc 1.03 only not 1.04. Check that out in the zip file.