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:
80 = 2 × 2 × 2 × 2 × 5 = 24 × 5
80 is a composite number.
Written with exponents:
12,345,678,980 = 2 × 2 × 5 × 61 × 10,119,409 = 22 × 5 × 61 × 10,119,409
12,345,678,980 is a composite number.
80/12,345,678,980 =
(80 ÷ 20) / (12,345,678,980 ÷ 20) =
4/617,283,949
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.
80/12,345,678,980 =
(24 × 5)/(22 × 5 × 61 × 10,119,409) =
((24 × 5) ÷ (22 × 5)) / ((22 × 5 × 61 × 10,119,409) ÷ (22 × 5)) =
22/(61 × 10,119,409) =
4/617,283,949
As a decimal number:
Simply divide the numerator by the denominator, without a remainder, as shown below:
4/617,283,949 =
4 ÷ 617,283,949 =
0.00000000648 ≈
0