2. Write the mixed repeating (recurring) decimal number as a proper fraction.
0.4285717 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 = 0.4285717
Set up the second equation.
- Number of decimal places repeating: 1
Multiply both sides of the first equation by 101 = 10
y = 0.4285717
10 × y = 10 × 0.4285717
10 × y = 4.285717
Get the same number of decimal places as for y:
10 × y = 4.2857177
Note: 4.2857177 = 4.285717
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 = 4.2857177 - 0.4285717 ⇒
(10 - 1) × y = 4.2857177 - 0.4285717 ⇒
We now have a new equation:
9 × y = 3.857146
Solve for y in the new equation.
9 × y = 3.857146 ⇒
y = 3.857146/9
Let the result written as a fraction.
Now we can write the number as a fraction.
According to our first equation:
y = 0.4285717
According to our calculations:
y = 3.857146/9
⇒ 0.4285717 = 3.857146/9
Get rid of the decimal places in the fraction above.
- Multiply the top and the bottom number by 1,000,000.
- 1 followed by as many 0-s as the number of digits after the decimal point.
0.4285717 = (3.857146 × 1,000,000)/(9 × 1,000,000)
0.4285717 = 3,857,146/9,000,000
3. Reduce (simplify) the fraction above:
3,857,146/9,000,000
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).
3,857,146 = 2 × 23 × 71 × 1,181
9,000,000 = 26 × 32 × 56
Calculate the greatest (highest) common factor (divisor), GCF.
Multiply all the common prime factors by the lowest exponents.
GCF (2 × 23 × 71 × 1,181; 26 × 32 × 56) = 2
Divide both the numerator and the denominator by their GCF.
3,857,146/9,000,000 =
(2 × 23 × 71 × 1,181)/(26 × 32 × 56) =
((2 × 23 × 71 × 1,181) ÷ 2) / ((26 × 32 × 56) ÷ 2) =
(23 × 71 × 1,181)/(25 × 32 × 56) =
1,928,573/4,500,000