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:
123,816 = 2 × 2 × 2 × 3 × 7 × 11 × 67 = 23 × 3 × 7 × 11 × 67
123,816 is a composite number.
Written with exponents:
308 = 2 × 2 × 7 × 11 = 22 × 7 × 11
308 is a composite number.
123,816/308 =
(123,816 ÷ 308) / (308 ÷ 308) =
402/1 =
402
* 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.
123,816/308 =
(23 × 3 × 7 × 11 × 67)/(22 × 7 × 11) =
((23 × 3 × 7 × 11 × 67) ÷ (22 × 7 × 11)) / ((22 × 7 × 11) ÷ (22 × 7 × 11)) =
(2 × 3 × 67)/1 =
(2 × 3 × 67) =
402
* When it's 1, the denominator of the fraction can be omitted.