How do you find the greatest common numerator?

Answer 1

You don't find the GCF of two fractions, you find the GCF of the numerator and denominator of one fraction in order to simplify it.

Example: 30/42

Factor them.

2 x 3 x 5 = 30

2 x 3 x 7 = 42

Select the common factors.

2 x 3 = 6, the GCF

30 divided by 6 = 5

42 divided by 6 = 7

30/42 = 5/7

If the GCF is 1, the fraction is in its simplest form.

Answer 2

That term doesn't exist as a practical matter. Since numbers don't stop, the greatest common numerator is infinite. You might be thinking of the least common denominator.