Converting between fractional and repeating decimal notation for rational numbers.

 

Converting from a fraction to a repeating decimal.

 

Simply divide the denominator of the fraction  into the numerator.  After the point where you are bringing down all zeros watch for a remainder that matches a previous one.  This will then define a cycle since the remainders will all repeat.

 

To convert from a repeating decimal  x to a fraction simply identify A as the number of decimal places to just before the repetition and B the number of placed to the end of the repetition.

 

Now take 10Bx and subtract 10Ax.  The values beyond the decimal place should line up so that the difference is a Natural number C.

 

x is  C / ( 10B - 10A )