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:
1,375 = 5 × 5 × 5 × 11 = 53 × 11
1,375 is a composite number.
123,750/1,375 =
(123,750 ÷ 1,375) / (1,375 ÷ 1,375) =
90/1 =
90
* 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.
123,750/1,375 =
(2 × 32 × 54 × 11)/(53 × 11) =
((2 × 32 × 54 × 11) ÷ (53 × 11)) / ((53 × 11) ÷ (53 × 11)) =
(2 × 32 × 5)/1 =
(2 × 32 × 5) =
90
* When it's 1, the denominator of the fraction can be omitted.