The Casio fx-21 is a scientific calculator with 8 digits precision and algebraic logic. It has 30 functions, 35 keys, and a VFD (vacuum fluorescent) display. The power source is 2xAA. The calculator was manufactured in Japan. Note: Boots 424; MBO fx-21 picture credit: Enrique García Simón
Facts at a glance:
You can download the Casio fx-21 manual from this external link.
If you have a Casio fx-21 that is no longer working, you can first try replacing the 2xAA batteries. If that doesn't solve the problem, then you can consider replacing the calculator with a modern equivalent. We suggest the following current model as a replacement: