If you have a scientific calculator, you can convert a decimal into a fraction and a fraction into a decimal. Scientific calculators have a button that has an "F" and a "D" on it with arrows pointing at each letter. This is the decimal to fraction and fraction to decimal conversion button. This is an important feature on the calculator because you will not need to make the conversion by hand, so it eliminates any chances of making mistakes.

Type the decimal into your calculator. For example, type 1.9.

Press "2nd."

Press the "F<>D" button to convert the fraction. The calculator will display "1_9/10."
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