Section 1: Getting Started 21
As you key in a number, notice how the HP-41C prompts you for each number with an _ (underscore).
To key in number 30.6593:
 Keystrokes Display 30.6593 30.6593 _ The number 30.6593, is in the display.
Numbers that you key in ALPHA mode are only ALPHA characters and cannot be used in number operations. For example, ALPHA g 4 ALPHA produces the ALPHA character 4. You cannot perform arithmetic operations on ALPHA numbers.
Numbers entered in ALPHA mode are ALPHA characters and cannot be used in number functions (i.e., + ,   , LOG ).
Negative Numbers
To key in a negative number, press the keys for the number, then press CHS (change sign). The number, preceded by a minus (–) sign, will appear in the display. For example, to change the sign of the number now in the display:
 Keystrokes Display CHS –30.6593 _
You can change the sign of either a negative of a positive nonzero number in the display. For example, to change the sign of the negative number now in the display back to positive:
 Keystrokes Display CHS 30.6593 _
Exponents of Ten
You can key in numbers with powers of 10 by pressing EEX (enter exponent of 10) followed by number keys to specify the exponent of 10. (Negative exponents are covered later.) Again, notice how the HP-41C prompts you for the number and the exponent. For example, to key in Avogadro's number (6.0222 × 1026):
Keystrokes Display
g CLX   0.0000
6.0222  6.0222 _   The HP-41C prompts you for each digit.
EEX
 6.0222 _
Then prompts you for the exponent.
2
 6.0222 2 _

6
 6.0222 26