The Highest Common Factor of three consecutive even numbers is:

Let's consider any three consecutive even numbers, for example: $4,6,8$.
Find the factors of each:

* $4=2\times 2$
* $6=2\times 3$
* $8=2\times 2\times 2$

The highest common factor among these three numbers is $2$.

Let's test another set of consecutive even numbers: $12,14,16$.

* $12=2\times 2\times 3$
* $14=2\times 7$
* $16=2\times 2\times 2\times 2$

Again, the only highest common factor is $2$.
Therefore, the HCF of any three consecutive even numbers is always $2$.