Casio fx-991ES PLUS Manual De Usuario

E-3

• Never try to take the calculator apart. 
• Use a soft, dry cloth to clean the exterior of the calculator. 
• Whenever discarding the calculator or batteries, be sure to do so in 

accordance with the laws and regulations in your particular area. 

* Company and product names used in this manual may be registered 

trademarks or trademarks of their respective owners. 

Before using the calculator, slide its hard 
case downwards to remove it, and then affix 
the hard case to the back of the calculator as 
shown in the illustration nearby.  

Press 

 to turn on the calculator.

Press 

(OFF) to turn off the calculator.

Auto Power Off
Your calculator will turn off automatically if you do not perform any operation 
for about 10 minutes. If this happens, press the 

 key to turn the calculator 

back on.

Display the CONTRAST screen by performing the following key operation: 
(SETUP)A(;CONT). Next, use B and C to adjust 
contrast. After the setting is the way you want, press 

. 

Important: If adjusting display contrast does not improve display readability, 
it probably means that battery power is low. Replace the battery.  

Pressing the 

 or   key followed by a second 

key performs the alternate function of the second key. 
The alternate function is indicated by the text printed 
above the key.  
The following shows what the different colors of the 
alternate function key text mean. 

Yellow

Press 

 and then the key to access the 

applicable function.

Red

Press 

  and then the key to input the 

applicable variable, constant, or symbol.

Purple (or enclosed 
in purple brackets)

Enter the CMPLX Mode to access the function.

Green (or enclosed in 
green brackets)

Enter the BASE-N Mode to access the function.

sin

–1   

D

s

sin

–1   

D

s