2. Write the mixed repeating (recurring) decimal number as a proper fraction.
0.307692309 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 = 0.307692309
Set up the second equation.
- Number of decimal places repeating: 1
Multiply both sides of the first equation by 101 = 10
y = 0.307692309
10 × y = 10 × 0.307692309
10 × y = 3.07692309
Get the same number of decimal places as for y:
10 × y = 3.076923099
Note: 3.076923099 = 3.07692309
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.
10 × y - y = 3.076923099 - 0.307692309 ⇒
(10 - 1) × y = 3.076923099 - 0.307692309 ⇒
We now have a new equation:
9 × y = 2.76923079
Solve for y in the new equation.
9 × y = 2.76923079 ⇒
y = 2.76923079/9
Let the result written as a fraction.
Now we can write the number as a fraction.
According to our first equation:
y = 0.307692309
According to our calculations:
y = 2.76923079/9
⇒ 0.307692309 = 2.76923079/9
Get rid of the decimal places in the fraction above.
- Multiply the top and the bottom number by 100,000,000.
- 1 followed by as many 0-s as the number of digits after the decimal point.
0.307692309 = (2.76923079 × 100,000,000)/(9 × 100,000,000)
0.307692309 = 276,923,079/900,000,000
3. Reduce (simplify) the fraction above:
276,923,079/900,000,000
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).
276,923,079 = 32 × 1,783 × 17,257
900,000,000 = 28 × 32 × 58
Calculate the greatest (highest) common factor (divisor), GCF.
Multiply all the common prime factors by the lowest exponents.
GCF (32 × 1,783 × 17,257; 28 × 32 × 58) = 32
Divide both the numerator and the denominator by their GCF.
276,923,079/900,000,000 =
(32 × 1,783 × 17,257)/(28 × 32 × 58) =
((32 × 1,783 × 17,257) ÷ 32) / ((28 × 32 × 58) ÷ 32) =
(1,783 × 17,257)/(28 × 58) =
30,769,231/100,000,000