2 is a common factor of 24 and 72.
This question mixes up two different concepts - that of the highest common factor (HCF) and lowest common multiple (LCM).
The Greatest Common Factor between 72 & 300 is 12, so (72/12) / (300/12) = 6/25
21 can not be divided by 2, ergo it can not be a common factor with 72
The lowest common multiple of 8 and 9 is 72.
The lowest common factor of any set of positive integers is 1.
The lowest factor of any positive integer is 1.
The least common factor of any set of numbers is 1.
The GCF is 6. The LCM is 72.
The lowest common multiple of 24 and 72 is 72.
The least common factor of any set of positive integers is 1.
They don't exist. The lowest common factor of any set of positive integers is always 1. 36, 72 and 108 have a greatest common factor of 36. 12, 18 and 36 have a least common multiple of 36.
All sets of numbers have an LCF of 1, so I'll assume you meant to write least common multiple. 6 and 72 have a GCF of 6 and an LCM of 72. So do 18 and 24.
2 is a common factor of 24 and 72.
72
The Least Common Multiple of two numbers is equal to their product divided by their greatest common factor.The greatest common factor of 72 and 42 is 6, so their Least Common Multiple is 72 * 42 / 6 = 504.
The GCF of 72 and 144 is 72. Since 72 is a factor of 144, it is automatically the GCF.