Write the greatest common factors of the numerator and denominator of the following fractions: 8 / 12, 15 / 21, 9 / 15, 6 / 18 emergency

Write the greatest common factors of the numerator and denominator of the following fractions: 8 / 12, 15 / 21, 9 / 15, 6 / 18 emergency

It's the greatest common divisor: 4, 3, 3, 6