2. Write the mixed repeating (recurring) decimal number as a proper fraction.
0.30769231 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 = 0.30769231
Set up the second equation.
- Number of decimal places repeating: 1
Multiply both sides of the first equation by 101 = 10
y = 0.30769231
10 × y = 10 × 0.30769231
10 × y = 3.0769231
Get the same number of decimal places as for y:
10 × y = 3.07692311
Note: 3.07692311 = 3.0769231
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 = 3.07692311 - 0.30769231 ⇒
(10 - 1) × y = 3.07692311 - 0.30769231 ⇒
We now have a new equation:
9 × y = 2.7692308
Solve for y in the new equation.
9 × y = 2.7692308 ⇒
y = 2.7692308/9
Let the result written as a fraction.
Now we can write the number as a fraction.
According to our first equation:
y = 0.30769231
According to our calculations:
y = 2.7692308/9
⇒ 0.30769231 = 2.7692308/9
Get rid of the decimal places in the fraction above.
- Multiply the top and the bottom number by 10,000,000.
- 1 followed by as many 0-s as the number of digits after the decimal point.
0.30769231 = (2.7692308 × 10,000,000)/(9 × 10,000,000)
0.30769231 = 27,692,308/90,000,000
3. Reduce (simplify) the fraction above:
27,692,308/90,000,000
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).
27,692,308 = 22 × 7 × 989,011
90,000,000 = 27 × 32 × 57
Calculate the greatest (highest) common factor (divisor), GCF.
Multiply all the common prime factors by the lowest exponents.
GCF (22 × 7 × 989,011; 27 × 32 × 57) = 22
Divide both the numerator and the denominator by their GCF.
27,692,308/90,000,000 =
(22 × 7 × 989,011)/(27 × 32 × 57) =
((22 × 7 × 989,011) ÷ 22) / ((27 × 32 × 57) ÷ 22) =
(7 × 989,011)/(25 × 32 × 57) =
6,923,077/22,500,000