Free Derangements - Subfactorials Calculator - Calculates the number of derangements/subfactorial !n.

Free Eulers Formula for Planar Geometry Calculator - This calculator solves for any one of the 3 following items using Eulers Formula for planar geometry:
* Vertices (v)
* Faces (f)
* Edges (e)

Free Eulers Totient (φ) Calculator - Given a positive integer (n), this calculates Euler's totient, also known as φ

Free Exponential Growth Calculator - This solves for any 1 of the 4 items in the exponential growth equation or exponential decay equation, Initial Value (P), Ending Value (A), Rate (r), and Time (t).

Free Logarithms and Natural Logarithms and Eulers Constant (e) Calculator - This calculator does the following:
* Takes the Natural Log base e of a number x Ln(x) → log_ex
* Raises e to a power of y, e^y
* Performs the change of base rule on log_b(x)
* Solves equations in the form b^cx = d where b, c, and d are constants and x is any variable a-z
* Solves equations in the form ce^dx=b where b, c, and d are constants, e is Eulers Constant = 2.71828182846, and x is any variable a-z
* Exponential form to logarithmic form for expressions such as 5³ = 125 to logarithmic form
* Logarithmic form to exponential form for expressions such as Log₅125 = 3

Free Mathematical Constants and Identities Calculator - Calculates and explains various mathematical constants such as:
* Gelfonds (Gelfond's) Constant
* Eulers Constant