What is the greatest common factor for 24 12 and 42?

Answer 1

Answer: 6

Since 12 is not a factor of 42, we can look right away at factors of 12 that are smaller than 12 itself.
6 is a factor of 12, and of 24 and of 42.
To see right away that it is the GCF, look for a factor of 12 that is bigger than 6,
7 is not
8 is not
9 is not
10 is not
11 is not

So we are left with 12

You could also factor the three numbers

24=23 x3
12=22 x3
42=7x3x2
Now take the smallest common factors
which are 2 and 3 since the highest power of 2 and 3 in 42 is 1.
There is no 7 in 24 or 12 so it is not a common factor

The answer is 2x3=6 as before.
What is the gcf of 24 12 and 42?

6

Answer 2

The greatest common factor (GCF) is: 6