Calculate a factorial
Multiply a whole number by every whole number below it, such as 6! = 720.
A factorial multiplies a whole number by every whole number below it, down to 1. For example 6! = 6 × 5 × 4 × 3 × 2 × 1 = 720.
Factorials grow very quickly. 69! is about the biggest one most calculators can show.
Classic Graphing 84
Start on the main screen: Press 2nd then mode (QUIT) to get back to the home screen. Pressing clear on a menu also backs out of it.
Type 6, then open the PROB menu (math, left, left) and choose ! (option 4).
6math◀◀4Press enter.
enter
You should see6! 720
Classic Scientific 30
Start on the main screen: Press 2nd then mode (QUIT) to leave any menu or screen and return to the calculation screen.
Type 6, then press prb and choose ! (option 3).
6prb3Press enter.
enter
You should see6! 720
Natural Scientific 991
Start on the main screen: Press MENU, then 1 (Calculate) to return to the main calculation screen. AC clears the line you are on.
Type 6, then SHIFT with the x⁻¹ key for x!.
6SHIFTx!x⁻¹Press =.
=
You should see6! 720
Natural Color Graphing
Start on the main screen: Press MENU then 1 to open Run-Matrix, the main calculation screen. Press EXIT to back out of a bar or screen, and SHIFT then EXIT (QUIT) to return to the app start.
Type 6, then open OPTN, move to its second page (F6) and choose PROB (F1). The first key is x!.
6OPTNF6F1F1Press EXE.
EXE
You should see6! 720
Classic CAS
Start on the main screen: Press home to open the Home menu (Calculator, Graphs, Settings, and more). Choose Calculator, or press esc to go back to the calculation page.
Type 6, then ctrl with the x key, which has ! printed above it.
6ctrl!xPress enter.
enter
You should see6! 720
RPN Scientific 15
Start on the main screen: There is no menu to leave. Press the back arrow to clear a number you are typing, or CLx (g then back arrow) to clear the X register.
Key in 6, then press f followed by 0, which is the x! function.
6fx!0
You should see720.0000
RPN Financial 12
Start on the main screen: There is no menu to leave: the display always shows the X register. Press f then R/S (P/R) to leave program mode, and clear a pending prefix by pressing ON.
Key in 6, then press g followed by 3, which is n!.
6gn!3
You should see720.00
RPN Advanced 42
Start on the main screen: Press EXIT (once or twice) to close any menu and return to the plain stack view of Y and X.
Open the PROB menu with shift then ×. Key in 6.
⇧PROB×6Press the third menu key, N!.
√x
You should seex: 720.0000
RPN Power 48
Start on the main screen: Press ON to cancel what you are typing, then use the stack view. Open the MODE or VAR menu any time; the stack is always shown above the menu row.
Key in 6. Open the MTH menu (apps then F1) and move to its third page with nxt twice.
6APPSF1NXTNXTPress F1 for the factorial.
F1
You should see1: 720
Tips
- 0! is defined as 1. Factorials only work on whole numbers that are zero or more.