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:
19,215 = 3 × 3 × 5 × 7 × 61 = 32 × 5 × 7 × 61
19,215 is a composite number.
Written with exponents:
50,000 = 2 × 2 × 2 × 2 × 5 × 5 × 5 × 5 × 5 = 24 × 55
50,000 is a composite number.
19,215/50,000 =
(19,215 ÷ 5) / (50,000 ÷ 5) =
3,843/10,000
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.
19,215/50,000 =
(32 × 5 × 7 × 61)/(24 × 55) =
((32 × 5 × 7 × 61) ÷ 5) / ((24 × 55) ÷ 5) =
(32 × 7 × 61)/(24 × 54) =
3,843/10,000
As a decimal number:
Simply divide the numerator by the denominator, without a remainder, as shown below:
3,843/10,000 =
3,843 ÷ 10,000 =
0.3843 ≈
0.38