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:
378 = 2 × 3 × 3 × 3 × 7 = 2 × 33 × 7
378 is a composite number.
Written with exponents:
20,000,000 = 2 × 2 × 2 × 2 × 2 × 2 × 2 × 2 × 5 × 5 × 5 × 5 × 5 × 5 × 5 = 28 × 57
20,000,000 is a composite number.
378/20,000,000 =
(378 ÷ 2) / (20,000,000 ÷ 2) =
189/10,000,000
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.
378/20,000,000 =
(2 × 33 × 7)/(28 × 57) =
((2 × 33 × 7) ÷ 2) / ((28 × 57) ÷ 2) =
(33 × 7)/(27 × 57) =
189/10,000,000
As a decimal number:
Simply divide the numerator by the denominator, without a remainder, as shown below:
189/10,000,000 =
189 ÷ 10,000,000 =
0.0000189 ≈
0