2. Write the pure repeating (recurring) decimal number as a proper fraction.
0.158 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 = 0.158
Set up the second equation.
- Number of decimal places repeating: 3
Multiply both sides of the first equation by 103 = 1,000
y = 0.158
1,000 × y = 1,000 × 0.158
1,000 × y = 158.158
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.
1,000 × y - y = 158.158 - 0.158 ⇒
(1,000 - 1) × y = 158.158 - 0.158 ⇒
We now have a new equation:
999 × y = 158
Solve for y in the new equation.
999 × y = 158 ⇒
y = 158/999
Let the result written as a fraction.
Now we can write the number as a fraction.
According to our first equation:
y = 0.158
According to our calculations:
y = 158/999
⇒ 0.158 = 158/999
3. Reduce (simplify) the fraction above:
158/999
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).
158 = 2 × 79
999 = 33 × 37
Calculate the greatest (highest) common factor (divisor), GCF.
Multiply all the common prime factors by the lowest exponents.
But, the numerator and the denominator have no common factors.
GCF (2 × 79; 33 × 37) = 1
The numerator and the denominator are coprime numbers (no common prime factors, GCF = 1). So, the fraction cannot be reduced (simplified): irreducible fraction.