fx-82MS fx-82TL fx-9860GII TI-83
x!
On a Casio calculator you can calculate the factorial of a natural number
▷ PROB x! OPTN F6 F3 F1
or via the CATALOG as
!
Example 1
To calculate 4! = 24 in RUN·MAT mode
▷ PROB x! 4 OPTN F6 F3 F1 4! EXE 4! 24
Example 2
! 0 ≣ EXE 0! 1
This is correct, because by definition is specified that 0! ≝ 1.