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:
123,750 = 2 × 3 × 3 × 5 × 5 × 5 × 5 × 11 = 2 × 32 × 54 × 11
123,750 is a composite number.
Written with exponents:
990 = 2 × 3 × 3 × 5 × 11 = 2 × 32 × 5 × 11
990 is a composite number.
123,750/990 =
(123,750 ÷ 990) / (990 ÷ 990) =
125/1 =
125
* 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.
123,750/990 =
(2 × 32 × 54 × 11)/(2 × 32 × 5 × 11) =
((2 × 32 × 54 × 11) ÷ (2 × 32 × 5 × 11)) / ((2 × 32 × 5 × 11) ÷ (2 × 32 × 5 × 11)) =
53/1 =
53 =
125
* When it's 1, the denominator of the fraction can be omitted.