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:
123,768 = 2 × 2 × 2 × 3 × 3 × 3 × 3 × 191 = 23 × 34 × 191
123,768 is a composite number.
Written with exponents:
216 = 2 × 2 × 2 × 3 × 3 × 3 = 23 × 33
216 is a composite number.
123,768/216 =
(123,768 ÷ 216) / (216 ÷ 216) =
573/1 =
573
* When it's 1, the denominator of the fraction can be omitted.
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.
123,768/216 =
(23 × 34 × 191)/(23 × 33) =
((23 × 34 × 191) ÷ (23 × 33)) / ((23 × 33) ÷ (23 × 33)) =
(3 × 191)/1 =
(3 × 191) =
573
* When it's 1, the denominator of the fraction can be omitted.