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:
19,719 = 3 × 3 × 7 × 313 = 32 × 7 × 313
19,719 is a composite number.
Written with exponents:
70,000 = 2 × 2 × 2 × 2 × 5 × 5 × 5 × 5 × 7 = 24 × 54 × 7
70,000 is a composite number.
19,719/70,000 =
(19,719 ÷ 7) / (70,000 ÷ 7) =
2,817/10,000
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.
19,719/70,000 =
(32 × 7 × 313)/(24 × 54 × 7) =
((32 × 7 × 313) ÷ 7) / ((24 × 54 × 7) ÷ 7) =
(32 × 313)/(24 × 54) =
2,817/10,000
As a decimal number:
Simply divide the numerator by the denominator, without a remainder, as shown below:
2,817/10,000 =
2,817 ÷ 10,000 =
0.2817 ≈
0.28