Press the [TAX+] key. You should now see "TAX" and "%" blinking on the display, and the screen should show "0".
| Step | Action | Key(s) to Press | Display / Result | |------|--------|----------------|------------------| | 1 | Turn on the calculator or clear any existing entries. | AC or CA | Display shows 0 . | | 2 | Enter the desired tax rate (e.g., 10%). | 1 0 | Display shows 10 . | | 3 | Press the key sequence. | RATE (or TAX SET ) then TAX+ | Confirm – some models beep or show TAX % . | | 4 | Verify the new rate. | Press RATE then TAX- | Display shows the newly stored rate. | | 5 | Exit setup mode. | AC or CA | Returns to calculation mode. | how to set tax rate in casio calculator