1.05.09 Expressing a fraction in its lowest form.
Method 2 prime factorisation.
Write the numerator and the denominator as a multiplication of their prime factors.
e.g., for 6/18.
- 6 = 1 x 2 x 3 .
- 18 = 1 x 2 x 3 x 3 .
- therefore 6/18, = 1 x 2 x 3/ 1 x 2 x 3 x 3 .
- dividing pairs of common factors in the numerator and denominator, 1/1 =1, 2/2 =1, 3/3 =1 .
- leaves 1 x 1 x 1 / 3, = 1/3 .
So the lowest form of the fraction is 1/3.
Note as the numbers in the numerator and denominator get larger, this method becomes more difficult and
method 1 is likely to be quicker.
