2. Write the mixed repeating (recurring) decimal number as a proper fraction.
0.123412341234 can be written as a proper fraction.
- The numerator is smaller than the denominator.
Set up the first equation.
- Let y equal the decimal number:
y = 0.123412341234
Set up the second equation.
- Number of decimal places repeating: 3
Multiply both sides of the first equation by 103 = 1,000
y = 0.123412341234
1,000 × y = 1,000 × 0.123412341234
1,000 × y = 123.412341234
Get the same number of decimal places as for y:
1,000 × y = 123.412341234234
Note: 123.412341234234 = 123.412341234
Subtract the first equation from the second one.
- Having the same number of decimal places ...
- The repeating pattern drops off by subtracting the two equations.
1,000 × y - y = 123.412341234234 - 0.123412341234 ⇒
(1,000 - 1) × y = 123.412341234234 - 0.123412341234 ⇒
We now have a new equation:
999 × y = 123.288928893
Solve for y in the new equation.
999 × y = 123.288928893 ⇒
y = 123.288928893/999
Let the result written as a fraction.
Now we can write the number as a fraction.
According to our first equation:
y = 0.123412341234
According to our calculations:
y = 123.288928893/999
⇒ 0.123412341234 = 123.288928893/999
Get rid of the decimal places in the fraction above.
- Multiply the top and the bottom number by 1,000,000,000.
- 1 followed by as many 0-s as the number of digits after the decimal point.
0.123412341234 = (123.288928893 × 1,000,000,000)/(999 × 1,000,000,000)
0.123412341234 = 123,288,928,893/999,000,000,000
3. Reduce (simplify) the fraction above:
123,288,928,893/999,000,000,000
to the lowest terms, to its simplest equivalent form, irreducible.
To reduce a fraction to the lowest terms divide the numerator and denominator by their greatest (highest) common factor (divisor), GCF.
Factor the numerator and denominator (prime factorization).
123,288,928,893 = 32 × 13 × 137 × 7,691,617
999,000,000,000 = 29 × 33 × 59 × 37
Calculate the greatest (highest) common factor (divisor), GCF.
Multiply all the common prime factors by the lowest exponents.
GCF (32 × 13 × 137 × 7,691,617; 29 × 33 × 59 × 37) = 32
Divide both the numerator and the denominator by their GCF.
123,288,928,893/999,000,000,000 =
(32 × 13 × 137 × 7,691,617)/(29 × 33 × 59 × 37) =
((32 × 13 × 137 × 7,691,617) ÷ 32) / ((29 × 33 × 59 × 37) ÷ 32) =
(13 × 137 × 7,691,617)/(29 × 3 × 59 × 37) =
13,698,769,877/111,000,000,000