To reduce a fraction to the lowest terms equivalent: divide the numerator and denominator by their greatest common factor, GCF
To calculate the greatest common factor, GCF:
- 1. Factor the numerator and the denominator (into prime factors), build their prime factorizations.
- 2. Multiply all their common prime factors, taken by the lowest exponents.
1. Factor the numerator and the denominator:
To factor a number (into prime factors) - or, in other words, to break it down to prime factors - or, in other words, to build its prime factorization: find the prime numbers that multiply together to get that number.
The prime factorizations:
645,170 = 2 × 5 × 149 × 433
645,170 is a composite number.
Written with exponents:
4,999,992 = 2 × 2 × 2 × 3 × 208,333 = 23 × 3 × 208,333
4,999,992 is a composite number.
645,170/4,999,992 =
(645,170 ÷ 2) / (4,999,992 ÷ 2) =
322,585/2,499,996
Yet another method to reduce the fraction
To reduce a fraction without calculating the GCF: factor its numerator and denominator, then all the common prime factors are easily identified and crossed out.
645,170/4,999,992 =
(2 × 5 × 149 × 433)/(23 × 3 × 208,333) =
((2 × 5 × 149 × 433) ÷ 2) / ((23 × 3 × 208,333) ÷ 2) =
(5 × 149 × 433)/(22 × 3 × 208,333) =
322,585/2,499,996
As a decimal number:
Simply divide the numerator by the denominator, without a remainder, as shown below:
322,585/2,499,996 =
322,585 ÷ 2,499,996 =
0.129034206455 ≈
0.13