I am assuming that this is for a 6-sided die. Let's look at the numbers that match the case of being even and being less than 6.
The numbers that are possible on the die are
1 2 3 4 5 6
If we match the criteria, what we have left is
1 2 3 4 5
(as a side note, if it were to say rolling an even number AND a number less than 6, the possibilities would be 2 and 4 only)
In this scenario, we have 5 numbers out of the total 6, so the probability would be 5/6 or around 83%
