Factorial key - Texas Instruments TI-84 Plus Calculator

1. Turn the phone off.
2. Press and hold the Power/Lock key (on the right side of the phone) and the Down Volume key (on the left side of the phone) at the same time.
3. When the Factory data reset screen appears, release both of the keys.
4. Use the Volume keys to highlight Factory data reset, then press the Power/Lock key to confirm.
5. Use the Volume keys to highlight Yes, then press the Power/Lock key to confirm one more time.
6. Your phone will perform a factory reset.

Perform a Master Reset via Hardware

1. To perform a hardware factory reset, press and hold the Volume down key followed by the Power key while the device is off.
2. Use the Volume down key to scroll to Wipe data/factory reset.
3. With Wipe data/factory reset highlighted, press the Power key.
4. Use the Volume down key to scroll to Yes.

http://www.fixya.com/support/t27097277-factory_reset_ans_ul40_smartphone

You would have to perform a factory reset to get back into the device. This removes all data on the tablet so if you can find the password that would be best.
To perform factory reset please follow those steps:
1. Power the device off.
2. Press and hold the Volume Up key and the Power key simultaneously to power on the device.
3. Release the Volume Up key and the Power key when the Samsung logo displays on the screen.
4. Use the Volume keys to select Recovery Console then press the Power key.
5. From the Recovery Console screen, use the Volume keys to select Wipe Data/Factory Reset then press the Power key.
6. Use the Volume keys to select Yes then press the Power key.
7. Once the Wipe Data / Factory Reset has completed, use the Volume keys to select Reboot System Now then press the Power key.
8. After a Wipe Data / Factory Reset has been performed, the device will need to go back through the activation and setup process

Restore factory default settings
When you restore the factory default settings, all personal settings are reset. Follow these instructions to restore the factory default settings.
All phone data will be deleted. Data on your SIM isn't deleted.

1. Find "Security Wipe"
Press the Menu key twice.
Scroll to Options and press the Navigation key.
Scroll to Security and press the Navigation key.
Scroll to Security Wipe and press the Navigation key.
2. Restore factory default settings
Highlight Emails, Contacts, etc., User Installed Applications or Media Card and press the Navigation key.
When the box next to the menu item is ticked (V), the selected data will be deleted.
Highlight the field at the bottom of the display and key in blackberry
Scroll to Wipe and press the Navigation key to restore the factory default settings.
Follow the instructions on the display

Performing factory data reset ( master reset or hard reset ) Samsung Galaxy Admire 2 SCH-R830C via External Hardware keys buttons by Entering Android System Recovery:

1. Turn off the device
2. Remove the battery about 10 second and reinsert, remove sim card and sd card
3. press and hold both the Volume Up key and the Power key until theSamsung logo is displayed.
4. Press the Volume Down key to scroll to wipe data/factory reset.
5. With wipe data/factory reset highlighted, press the Power key.
6. Press the Volume Down key to scroll to Yes - delete all user data.
7. Press the Power key to confirm.
8. Press the Volume Down key to scroll to wipe cache partition.
9. With wipe cache partition highlighted, press the Power key.
10. Once the wipe is complete, press the Power key to select reboot system now.

Warning! All data will be erased from device memory, including system and application data, settings and downloaded applications. Back up your important data. The device will restore to factory settings.

In Run screen enter the number whose factorial you want to calculate, then press OPTN. Using F6> pan the tabs till you see PROB. Press the key that is under the tab. You will find the factorial function.

It's the shifted function of the x^-1 key, located just below and right of the big round cursor pad, above the log key.

Yes, you have PATS II. There is a tranceiver on the ignition barrel and a transponder in every factory key. If the transceiver cannot read your key, the red security light will blink rapidly.If this happens, make sure you are using a factory key and there are no other factory keys near the switch. If it continues to blink rapidly, you might try removing the PATS ring from the key barrel and placing a factory key in the center of the ring. I have done this successfully in the past. If it works, tape up the key inside the ring and place it in the open space in the steering column shroud. Then remove the transponder from any other factory keys. You can then have keys made at a hardware store, as your one transponder inside the column will constantly respond to the PATS system.

It all depends on what calculator you have.

For the TI-89, Press 2ND, then press 5, then press 7, then press enter.

The the TI-84, Press 2ND, then press 0, then press 3, then press enter.

I do not believe the TI-30 can do factorials.