2. Write the mixed repeating (recurring) decimal number as a proper fraction.
0.485 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 = 0.485
Set up the second equation.
- Number of decimal places repeating: 2
Multiply both sides of the first equation by 102 = 100
y = 0.485
100 × y = 100 × 0.485
100 × y = 48.585
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 = 48.585 - 0.485 ⇒
(100 - 1) × y = 48.585 - 0.485 ⇒
We now have a new equation:
99 × y = 48.1
Solve for y in the new equation.
99 × y = 48.1 ⇒
y = 48.1/99
Let the result written as a fraction.
Now we can write the number as a fraction.
According to our first equation:
y = 0.485
According to our calculations:
y = 48.1/99
⇒ 0.485 = 48.1/99
Get rid of the decimal places in the fraction above.
- Multiply the top and the bottom number by 10.
- 1 followed by as many 0-s as the number of digits after the decimal point.
0.485 = (48.1 × 10)/(99 × 10)
0.485 = 481/990
3. Reduce (simplify) the fraction above:
481/990
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).
481 = 13 × 37
990 = 2 × 32 × 5 × 11
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 (13 × 37; 2 × 32 × 5 × 11) = 1
The numerator and the denominator are coprime numbers (no common prime factors, GCF = 1). So, the fraction cannot be reduced (simplified): irreducible fraction.