What is the greatest common factor of 30 64 42 196?

Answer 1

the only factor (divisor) between 30 and 64 are 2, this is also a factor of 42 & 196

working upwards:

1 is always a factor of integers

2 is a factor of all even numbers

3 is a factor of 30 & 42, but not 64 or 196

4 is a factor of 64 & 196, but not 30 or 42

5 is a factor of 30, but not the others

6 is a factor of 30 & 42, but not 64 or 196

7 is a factor of 42, but not the others

8 is a factor of 64, but not the others

9 is not a factor of any of the numbers

10 is a factor of 30, but not the others

I could continue, but it gets worse from there, with only occasional numbers being factors...