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:
4 = 2 × 2 = 22
4 is a composite number.
Written with exponents:
5,000,000,000 = 2 × 2 × 2 × 2 × 2 × 2 × 2 × 2 × 2 × 5 × 5 × 5 × 5 × 5 × 5 × 5 × 5 × 5 × 5 = 29 × 510
5,000,000,000 is a composite number.
4/5,000,000,000 =
(4 ÷ 4) / (5,000,000,000 ÷ 4) =
1/1,250,000,000
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.
4/5,000,000,000 =
22/(29 × 510) =
(22 ÷ 22) / ((29 × 510) ÷ 22) =
1/(27 × 510) =
1/1,250,000,000
As a decimal number:
Simply divide the numerator by the denominator, without a remainder, as shown below:
1/1,250,000,000 =
1 ÷ 1,250,000,000 =
0.0000000008 ≈
0