Question

What are the common factors of `6` and `4` ?

Answer 1

The only positive integer factors they have in common are `1` and `2`.

Explanation:

The positive integer factors of `6` are `1, 2, 3, 6`

The positive integer factors of `4` are `1, 2, 4`

So the only ones they have in common are `1` and `2`

Notes

In contexts where we need to consider negative factors, we would also recognise `-1, -2, -3, -6` as factors of `6` and `-1, -2, -4` as factors of `4`.

So the common integer factors of `6` and `4` are `1, -1, 2, -2`

Advanced Footnote (for interest only)

In the context of Gaussian integers, the common factors of `6` and `4` are:

`1, -1, i, -i, 1+i, 1-i, -1+i, -1-i, 2, -2, 2i, -2i`