Calculator that solves more than 15 problems and demonstrates how it was solved.
Those problems are:
*sum
*sub
*multiplication
*division
*linear equation
*quadratic equation
*inequalities
*rule of 3
*log
*ln
*sin(x)
*cos(x)
*tan(x)
*Mod
*pi
*e
Also, see the version with more functions: Calculator Board.