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:
123,795 = 3 × 3 × 3 × 5 × 7 × 131 = 33 × 5 × 7 × 131
123,795 is a composite number.
Written with exponents:
945 = 3 × 3 × 3 × 5 × 7 = 33 × 5 × 7
945 is a composite number.
123,795/945 =
(123,795 ÷ 945) / (945 ÷ 945) =
131/1 =
131
* 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.
123,795/945 =
(33 × 5 × 7 × 131)/(33 × 5 × 7) =
((33 × 5 × 7 × 131) ÷ (33 × 5 × 7)) / ((33 × 5 × 7) ÷ (33 × 5 × 7)) =
131/1 =
131
* When it's 1, the denominator of the fraction can be omitted.