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:
123,690 = 2 × 3 × 5 × 7 × 19 × 31
123,690 is a composite number.
42 = 2 × 3 × 7
42 is a composite number.
123,690/42 =
(123,690 ÷ 42) / (42 ÷ 42) =
2,945/1 =
2,945
* When it's 1, the denominator of the fraction can be omitted.
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.
123,690/42 =
(2 × 3 × 5 × 7 × 19 × 31)/(2 × 3 × 7) =
((2 × 3 × 5 × 7 × 19 × 31) ÷ (2 × 3 × 7)) / ((2 × 3 × 7) ÷ (2 × 3 × 7)) =
(5 × 19 × 31)/1 =
(5 × 19 × 31) =
2,945
* When it's 1, the denominator of the fraction can be omitted.
As a percentage:
- A percentage value p% is equal to the fraction: p/100, for any decimal number p. So, we need to change the form of the number calculated above, to show a denominator of 100.
- To do that, multiply the number by the fraction 100/100.
- The value of the fraction 100/100 = 1, so by multiplying the number by this fraction the result is not changing, only the form.
2,945 =
2,945 × 100/100 =
(2,945 × 100)/100 =
294,500/100 =
294,500%
- In other words:
- (1) Calculate the fraction's value, (2) multiply that number by 100, and (3) add the percent sign % to it.
The final answer:
written in three ways