Here is a simple way to make sure that a Casio Scientific calculator works porperly before you take it home from the shop. Scientific calulators have got a whole lot of functions built on to it and all those functions cannot be checked in one go. The manufacturer has added a built in check for the calculator. Here is how to do it.
Turn on the calulator
Press the key combination : 'shift' + '7' + 'on'. The display will be fully dark showing every pixel of the calculator.
Press 'shift' again and the display goes blank. keep pressing 'shift' and you will see numbers displayed. This will end after displaying ' 1 '. Then press the key right to shift and you will get 2. Likewise pressing the adjacent switches displays numbers in ascending order. Do not forget to include the wheel in this procedure. The wheel is a group of 4 buttons.
Atlast when you press ' = ' button the display will show 'ok'. This means that your calculator is tested and is working fine.
If the series of numbers gets stuck somewhere then the calculator has got a problem. Remember to do this check while you purchase the calculator so that you will have all the functions available in it.
This procedure has been tested by myself on various calculators in the casio - 'fx' series and in the casio '991es' calculator. But this must work on other models. Try them for yourself.
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