Condition ERROR
Casio Casio Calculator
Severity: MinorWhat it means
Condition ERROR means the calculation cannot be performed in the current mode or with the current settings.
You may be trying to use a function that requires a specific mode (STAT, Complex, etc.).
Switch to the correct mode.
Affected Models
- Casio fx-991EX
- Casio fx-991ES Plus
- Casio fx-CG50
Common Causes
- Using a statistics function outside STAT mode
- Using complex numbers in Real mode
- Using a function not available in the current calculation mode
- Attempting base-N operations in wrong mode
How to Fix It
-
Switch to the correct mode for your calculation.
Press MENU (or MODE) and select the appropriate mode:
Complex, Statistics, Base-N, Equation, etc. -
For complex numbers: switch to Complex mode.
MENU > Complex (or a+bi mode).
Real mode does not allow complex number operations. -
For statistics: switch to STAT mode first.
MENU > Statistics.
Enter data before using stat functions.
Frequently Asked Questions
How many modes does the fx-991EX have?
The fx-991EX has modes for: Calculate, Complex, Base-N, Matrix, Vector, Statistics, Spreadsheet, Table, Equation, Inequality, Ratio, and Distribution.
Does mode affect my stored values?
Switching modes does not delete stored variables.
But some variables are mode-specific (like statistical data).