2. Write the pure repeating (recurring) decimal number as an improper fraction.
28.9 can be written as an improper fraction.
- The numerator larger than or equal to the denominator.
Set up the first equation.
- Let y equal the decimal number:
y = 28.9
Set up the second equation.
- Number of decimal places repeating: 1
Multiply both sides of the first equation by 101 = 10
y = 28.9
10 × y = 10 × 28.9
10 × y = 289.9
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 = 289.9 - 28.9 ⇒
(10 - 1) × y = 289.9 - 28.9 ⇒
We now have a new equation:
9 × y = 261
Solve for y in the new equation.
9 × y = 261 ⇒
y = 261/9
Let the result written as a fraction.
Now we can write the number as a fraction.
According to our first equation:
y = 28.9
According to our calculations:
y = 261/9
⇒ 28.9 = 261/9
3. Reduce (simplify) the fraction above:
261/9
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).
261 = 32 × 29
9 = 32
Calculate the greatest (highest) common factor (divisor), GCF.
Multiply all the common prime factors by the lowest exponents.
GCF (32 × 29; 32) = 32
Divide both the numerator and the denominator by their GCF.
261/9 =
(32 × 29)/32 =
((32 × 29) ÷ 32) / (32 ÷ 32) =
29/1
Note:: 29/1 = 29