2. Write the pure repeating (recurring) decimal number as a proper fraction.
0.69 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 = 0.69
Set up the second equation.
- Number of decimal places repeating: 2
Multiply both sides of the first equation by 102 = 100
y = 0.69
100 × y = 100 × 0.69
100 × y = 69.69
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.
100 × y - y = 69.69 - 0.69 ⇒
(100 - 1) × y = 69.69 - 0.69 ⇒
We now have a new equation:
99 × y = 69
Solve for y in the new equation.
99 × y = 69 ⇒
y = 69/99
Let the result written as a fraction.
Now we can write the number as a fraction.
According to our first equation:
y = 0.69
According to our calculations:
y = 69/99
⇒ 0.69 = 69/99
3. Reduce (simplify) the fraction above:
69/99
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).
69 = 3 × 23
99 = 32 × 11
Calculate the greatest (highest) common factor (divisor), GCF.
Multiply all the common prime factors by the lowest exponents.
GCF (3 × 23; 32 × 11) = 3
Divide both the numerator and the denominator by their GCF.
69/99 =
(3 × 23)/(32 × 11) =
((3 × 23) ÷ 3) / ((32 × 11) ÷ 3) =
23/(3 × 11) =
23/33