How to Convert Repeating Decimals to Fractions

Step-by-Step Guide

1. 1

   Step 1: Locate the repeating decimal.

   For instance, the number
   0.4444 has a repeating decimal of
   4.
   
   It is a basic repeating decimal in the sense that there's no non-repeating portion to the decimal number.
   
   Count how many repeating digits there are in the pattern.
   
   Once your equation is written, you will multiply it by 10^y, where y equals the number of repeating digits in the pattern.In the example of
   0.4444, there is one digit that repeats, so you will multiply the equation by 10^1.
   
   For a repeating decimal of
   0.4545, there are two digits that repeat, and you would, therefore, multiply your equation by 10^2.
   
   For three repeating digits, multiply by 10^3, etc.
2. 2

   Step 2: Rewrite the decimal as an equation.

   Write it out so that x equals the original number.
   
   In this instance, the equation is x =
   0.4444.
   
   Since there’s only one digit in the repeating decimal, multiply the equation by 10^1 (which equals 10).In the example where x =
   0.4444, then 10x =
   4.4444.
   
   With the example x =
   0.4545, there are two repeating digits, so you multiply both sides of the equation by 10^2 (which equals 100), giving you 100x =
   45.4545. , You accomplish this by subtracting x from 10x.
   
   Remember that whatever you do to one side of the equation must be done to the other, so:10x – 1x =
   4.4444 –
   0.4444 On the left side, you have10x
   - 1x = 9x.
   
   On the right side, you have
   4.4444 –
   0.4444 = 4 Therefore, 9x = 4 , Once you know what 9x equals, you can determine what x equals by dividing both sides of the equation by 9:
   On the left side of the equation you have 9x ÷ 9 = x.
   
   On the right side of the equation you have 4/9 Therefore, x = 4/9, and the repeating decimal
   0.4444 can be written as the fraction 4/9. , Put the fraction in its simplest form (if applicable) by dividing both the numerator and denominator by the greatest common factor.In the example of 4/9, that is the simplest form. , It’s not uncommon for a number to have non-repeating digits before the repeating decimal, but these can still be converted into fractions.
   
   For example, take the number
   6.215151.
   
   Here,
   6.2 is non-repeating, and the repeating digits are
   15.
   
   Again take note of how many repeating digits there are in the pattern, because you will multiply by 10^y based on that number.
   
   In this example, there are two repeating digits, so you will multiply your equation by 10^2. , Again, if x =
   6.215151, then 100x =
   621.5151.
   
   To remove the repeating decimals, subtract from both sides of the equation: 100x – x (= 99x) =
   621.5151
   -
   6.215151 (=
   615.3) Therefore, 99x =
   615.3 , Since 99x =
   615.3, divide both sides of the equation by
   99.
   
   This gives you x =
   615.3/99. , Do this by multiplying the numerator and denominator by 10^z, where z equals the number of decimal places you must move to eliminate the decimal.
   
   In
   615.3, you have to move the decimal by one place, meaning you multiply the numerator and denominator by 10^1:
   615.3 x 10 / 99 x 10 = 6153/990 Reduce the fraction by dividing the numerator and denominator by the highest common factor, which in this case is 3, giving you x = 2,051/ 330
3. 3

   Step 3: Remove the repeating decimal.

4. 4

   Step 4: Solve for x.

5. 5

   Step 5: Reduce the fraction.

6. 6

   Step 6: Determine the repeating digits.

7. 7

   Step 7: Write the problem as an equation and subtract the repeating decimals.

8. 8

   Step 8: Solve for x.

9. 9

   Step 9: Remove the decimal in the numerator.

Detailed Guide

About the Author