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:
1,020 = 2 × 2 × 3 × 5 × 17 = 22 × 3 × 5 × 17
1,020 is a composite number.
Written with exponents:
4,892 = 2 × 2 × 1,223 = 22 × 1,223
4,892 is a composite number.
1,020/4,892 =
(1,020 ÷ 4) / (4,892 ÷ 4) =
255/1,223
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.
1,020/4,892 =
(22 × 3 × 5 × 17)/(22 × 1,223) =
((22 × 3 × 5 × 17) ÷ 22) / ((22 × 1,223) ÷ 22) =
(3 × 5 × 17)/1,223 =
255/1,223
As a decimal number:
Simply divide the numerator by the denominator, without a remainder, as shown below:
255/1,223 =
255 ÷ 1,223 =
0.208503679477 ≈
0.21