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Casio fx-991EX keeps giving math error for simple calculations like ((1/2)/2) and sin inverse (10) etc. Any idea on how to fix this? Is there a chance that the calculator may be
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Why does the German version of the Casio fx-991EX, the fx-991DE X, have more functions than the US version? : r/calculators
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Which scientific calculator is better for mechanical engineers, a Casio FX- 991ES, a Texas instruments TI-36 X or a Casio FX115 ES? - Quora
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Why does the German version of the Casio fx-991EX, the fx-991DE X, have more functions than the US version? : r/calculators
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![Why does the German version of the Casio fx-991EX, the fx-991DE X, have more functions than the US version? : r/calculators Why does the German version of the Casio fx-991EX, the fx-991DE X, have more functions than the US version? : r/calculators](http://i.imgur.com/Wu9vfjF.png)
Why does the German version of the Casio fx-991EX, the fx-991DE X, have more functions than the US version? : r/calculators
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