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:
Written with exponents:
18 = 2 × 3 × 3 = 2 × 32
18 is a composite number.
4,000,000,017 = 3 × 13 × 102,564,103
4,000,000,017 is a composite number.
18/4,000,000,017 =
(18 ÷ 3) / (4,000,000,017 ÷ 3) =
6/1,333,333,339
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.
18/4,000,000,017 =
(2 × 32)/(3 × 13 × 102,564,103) =
((2 × 32) ÷ 3) / ((3 × 13 × 102,564,103) ÷ 3) =
(2 × 3)/(13 × 102,564,103) =
6/1,333,333,339
As a decimal number:
Simply divide the numerator by the denominator, without a remainder, as shown below:
6/1,333,333,339 =
6 ÷ 1,333,333,339 =
0.0000000045 ≈
0