Pairwise combination of 1, 2, 3, 4, 5, A5(2)=20

When the unit is 2.

Pairwise combination of 0, 1, 3, 4, 5

A5(2)=20, where 0 cannot start.

So there are four groups missing.

It is 16 group.

When the unit is 4.

Pairwise combination of 0, 1, 3, 4, 5

A5(2)=20, where 0 cannot start.

So there are four groups missing.

It is 16 group.

Therefore, the even number of three digits consisting of 0, 1, 2, 3, 4 and 5 is 20+ 16+ 16=52.