Replacing the Battery
fx-991CW sold in the US and Canada: For safety reasons, please do not replace the battery yourself. Always leave battery replacement up to an authorized CASIO service center.
If the screen shown below appears right after you turn on power, it means that remaining battery power is low.
A low battery is also indicated by a dim display, even if contrast is adjusted, or by failure of figures to appear on the display immediately after you turn on the calculator.
If this happens or the above screen appears, replace the battery with a new one.
Important!
Removing the battery causes all of the calculator’s memory contents to be cleared.
1. Press 
(OFF) to turn off the calculator.
To ensure that you do not accidentally turn on power while replacing the battery, attach the front cover to the front of the calculator.
2. As shown in the illustration, remove the battery cover, remove the battery, and then load a new battery with its plus (+) and minus (−) ends facing correctly.
3. Replace the battery cover.
4. Press 
to turn on the calculator.
5. Initialize the calculator.
(1) Press 
, select a calculator app icon, and then press 
.
(2) Press 
, and then select [Reset] > [Initialize All] > [Yes].
Do not skip the above steps!
