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:
16,905 = 3 × 5 × 7 × 7 × 23 = 3 × 5 × 72 × 23
16,905 is a composite number.
Written with exponents:
25,000 = 2 × 2 × 2 × 5 × 5 × 5 × 5 × 5 = 23 × 55
25,000 is a composite number.
16,905/25,000 =
(16,905 ÷ 5) / (25,000 ÷ 5) =
3,381/5,000
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.
16,905/25,000 =
(3 × 5 × 72 × 23)/(23 × 55) =
((3 × 5 × 72 × 23) ÷ 5) / ((23 × 55) ÷ 5) =
(3 × 72 × 23)/(23 × 54) =
3,381/5,000
As a decimal number:
Simply divide the numerator by the denominator, without a remainder, as shown below:
3,381/5,000 =
3,381 ÷ 5,000 =
0.6762 ≈
0.68