A0TOMATH
This is a somewhat useful program that consist of a collection of auto-solvers. You push a buttom with green letter to select the solver you need
A: calculate A!
B: calculate A!/B!
The issue with using the built in factorial calculator is that it is limited to 69.5! and below (due to TI84+ giving an error message if any anser is bigger than 10^100, this is for aesthetic reasons only).
One current limitation is that it doesn't work for negative numbers so it's not the complete gamma-function, still better than the built-in factorial that is limited to half-integers
C: solve a second order equation
The roots will be given as the calculator variables (X, Y).
D: solve a cubic equation
The roots will be given as the calculator variables (X, Y, Z).
E: solve a forth order equation
The roots will be given as the calculator variables (X, Y, Z, θ).
F to N solves for a triangle where 3 is known (area, angles, sides)
O: this will calculate the number of permutations for arbitrary number of object types.
If you input (3,4,5,6,0) it will calculate (3+4+5+6)! / 3! / 4! / 5! / 6!
If you input (3,4,5,-30) it will calculate 30! / 3! / 4! / 5! / 18!