Calculating a Factorial

In mathematics, ! is used to represent a factorial, as in 5! = 5 x 4 x 3 x 2 x 1 = 120. To calculate7!, first type 7 on the home screen, then press the MATH key, then the RIGHT ARROW three times to highlight PRB. Press 4 to select 4:!, and a ! is placed after the same on the home screen. Press ENTER and the results are shown. 7! = 5040.