Let's say we want to reduce:
33
----
44
Here's an example:
Fraction: 33/44.
Factors:
33: {1, 3, 11, 33}.
44: {1, 2, 4, 11, 22, 44}.
GCF: 11.
Divide the numerator and the denominator:
33/11 = 3.
44/11 = 4.
Answer: 3/4.