2. Write the mixed repeating (recurring) decimal number as a proper fraction.
0.8571428575 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 = 0.8571428575
Set up the second equation.
- Number of decimal places repeating: 1
Multiply both sides of the first equation by 101 = 10
y = 0.8571428575
10 × y = 10 × 0.8571428575
10 × y = 8.571428575
Get the same number of decimal places as for y:
10 × y = 8.5714285755
Note: 8.5714285755 = 8.571428575
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 = 8.5714285755 - 0.8571428575 ⇒
(10 - 1) × y = 8.5714285755 - 0.8571428575 ⇒
We now have a new equation:
9 × y = 7.714285718
Solve for y in the new equation.
9 × y = 7.714285718 ⇒
y = 7.714285718/9
Let the result written as a fraction.
Now we can write the number as a fraction.
According to our first equation:
y = 0.8571428575
According to our calculations:
y = 7.714285718/9
⇒ 0.8571428575 = 7.714285718/9
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.
0.8571428575 = (7.714285718 × 1,000,000,000)/(9 × 1,000,000,000)
0.8571428575 = 7,714,285,718/9,000,000,000
3. Reduce (simplify) the fraction above:
7,714,285,718/9,000,000,000
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).
7,714,285,718 = 2 × 1,117 × 3,453,127
9,000,000,000 = 29 × 32 × 59
Calculate the greatest (highest) common factor (divisor), GCF.
Multiply all the common prime factors by the lowest exponents.
GCF (2 × 1,117 × 3,453,127; 29 × 32 × 59) = 2
Divide both the numerator and the denominator by their GCF.
7,714,285,718/9,000,000,000 =
(2 × 1,117 × 3,453,127)/(29 × 32 × 59) =
((2 × 1,117 × 3,453,127) ÷ 2) / ((29 × 32 × 59) ÷ 2) =
(1,117 × 3,453,127)/(28 × 32 × 59) =
3,857,142,859/4,500,000,000